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OF THE 

UNIVERSITY 
Of ILLINOIS 



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Latest Date stamped below. A 
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M32 



A NEW CATALOGUE 

OF THE 

FRESH-WATER FISHES OF PANAMA 



BY 

SAMUEL F. HILDEBRAND 

SENIOR ICHTHYOLOGIST 
UNITED STATES BUREAU OF FISHERIES 




THE LIBRARY OF THE 

OCT121938 

UNIVERSITY OF ILLINOIS 

ZOOLOGICAL SERIES 

FIELD MUSEUM OF NATURAL HISTORY 

VOLUME XXII, NUMBER 4 

SEPTEMBER 28. 1938 

PUBLICATION 425 



PRINTED IN THE UNITED STATES OF AMERICA 
BY FIELD MUSEUM PRESS 



CONTENTS 

PACK 

Introduction 219 

Notes on the Origin and Distribution of Panama Fishes . . 221 

Introduction of Fishes 225 

New and Abandoned Localities 228 

Acknowledgments 230 

New Species Described 231 

Catalogue of Species ' 231 

References . . 357 



217 



A NEW CATALOGUE OF THE FRESH-WATER 
FISHES OF PANAMA 1 



BY SAMUEL F. HILDEBRAND 



INTRODUCTION 

The present paper embodies the results of a study based mainly 
on specimens and data collected by the writer in 1935 and 1937. 
This study was supplemented by information gained from the 
examination of small collections made by others. Furthermore, 
some of the material collected in 1911 and 1912 by the late Dr. Seth 
E. Meek and the writer, was re-examined for further information. 

The Fishes of the Fresh Waters of Panama by Seth E. Meek and 
the writer, published by Field Museum in 1916, has been drawn 
upon freely. The present paper is intended to supplement this 
earlier general work. Errors in that publication have been pointed 
out, descriptions have been emended if necessary, and in some 
instances new keys have been given to include species since recorded. 
All the species described in the earlier work are mentioned in the 
present one, together with such additional information as seems 
worthy of record, including the up-to-date knowledge of distribution. 
Descriptions, or at least sufficient information for identification of 
species not included in the general account of 1916, are given in the 
present paper. In the synonymy only the names used by the original 
describers are given, together with a reference to our earlier general 
work; if not included therein a reference to other writers who have 
recorded the species from Panama is included. 

The principal papers on fresh-water fishes of Panama, that have 
appeared since 1916 are The Fishes of the Rio Chucunaque Drainage, 
Eastern Panama, by C. M. Breder, Jr. (1927), and A List of the Fresh 
Water Fishes of Western Panama between Long. 81 45' and 83 15' W., 
by Dr. Ellinor H. Behre (1928). These reported a considerable num- 
ber of species previously not recorded from Panama. Several 
smaller papers have appeared, and are referred to in appropriate 
places in the accounts of species, and are listed in the "References." 
Unfortunately, comparatively few of the specimens on which these 
later papers were based have been available to me for examination. 

The number of species reported from the fresh waters of the 
Republic in our earlier (1916) work has been increased from 94 to 127. 

1 Published by permission of the United States Commissioner of Fisheries. 
219 



220 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

A further increase is expected, as most of western Panama, and a 
considerable part of the Atlantic slope of eastern Panama remain 
ichthyologically virtually unexplored. 

The designations western, central, and eastern Panama are used 
freely in this paper. It is understood, of course, that there are no 
such political divisions. As here used western Panama includes the 
states of Bocas del Toro and Chiriqui, while central Panama includes 
the Canal Zone and the territory westward on the Pacific slope a 
distance of about 70 miles. The Atlantic slope west of the Canal 
Zone is not included because no collections have been made there, 
except at Bocas del Toro, which is included in western Panama. 
Eastward, central Panama includes the territory as far as Porto 
Bello on the Atlantic and the Bayano Basin on the Pacific. Eastern 
Panama consists principally of the Tuyra Basin, including two 
large rivers, the Tuyra and the Chucunaque. The narrow Atlantic 
slope from Porto Bello to the Colombian border remains virtually 
unexplored. 

Only those species which live more or less constantly in fresh 
water are included. A few, such as some of the Gobiidae (now 
usually placed in a separate family, Eleotridae), and a few of the 
Poeciliidae, descend to brackish water. On the other hand, several 
species belonging to marine families, which dwell in the fresh water 
of Panama more or less commonly, such as one of the Syngnathidae 
(Doryrhamphus lineatus}, one of the Atherinidae (Menidia chagresi), 
several species of Centropomidae, the tarpon, and several others, 
are not included. These will be dealt with mostly in a paper now in 
preparation, pertaining to the use of the Panama Canal and its locks 
as a passageway for fishes. 

Two papers (Hildebrand, 1935 and 1937) based on these investi- 
gations have been published. It is proposed also to publish one or 
more papers on extensive collections of marine fishes made on both 
coasts of Panama, and the Pearl Islands, wherein species ranging into 
fresh water probably will be dealt with still further. It may be added 
that marine fishes have invaded the fresh water of the Canal to a 
remarkable degree. 

The order of families, genera, and species used in our earlier work 
has been retained as far as practicable. Only such changes in nomen- 
clature as seemed well founded have been made. Wherever recently 
proposed changes in nomenclature of families and genera have not 
been followed the reasons are stated. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 221 

The proportions and counts given were derived by the same 
methods as in the earlier work. It seems sufficient to state only 
that the scale counts, unless otherwise stated, show the number of 
oblique series of scales (running upward and backward) crossing a 
straight line between the upper anterior angle of the gill opening and 
the base of the caudal. The counts in Arabic numerals of soft rays of 
the fins include undivided or rudimentary rays, unless otherwise stated. 
Definitely developed spines are always given in Roman numerals. 

NOTES ON THE ORIGIN AND DISTRIBUTION 
OF PANAMA FISHES 

It was pointed out in our earlier work that the fresh-water fishes 
of Panama, known at that time, when western Panama remained 
unexplored, were chiefly of South American origin. Principally 
through the work of Dr. Behre (1928) it has since been learned that 
the fish fauna of western Panama is composed largely of Central 
American forms. In fact, comparatively few of the species of central 
Panama have been taken in western Panama. 

The Loricariidae, with one exception (Plecostomus plecostomus 
panamensis), apparently do not reach western Panama, though 
seven species, some of which are common, are found in central 
Panama. 

The Characinidae are much less numerous in western than in 
central Panama, and the species found there are largely different. 
Only nine species are known from western Panama, whereas 32 are 
reported in this paper from central and eastern Panama, and only 
two (possibly three) are common to both regions. 

It is evident, then, that the Loricariidae and the Characinidae, 
two large and rather typical South American families of fresh-water 
fishes, mostly reach the northern (western) limits of their range in 
central Panama. A similar distribution, that is, dissimilarity of 
species, exists among other families, though perhaps less clearly. 

On the other hand, the family Cichlidae, which is more numerous 
in Central than in South America, has a larger number of representa- 
tives in western than in central Panama, there being 11 species 
recorded from the first-mentioned region and six (two of which are 
doubtful) from the last-mentioned one. Three (possibly four) are 
common to both regions. 

Because of the unexplored intermediate territory, it cannot yet 
be stated where the Central American fauna ends and the South 
American one begins, if in fact a definite division exists. 



222 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Meager data suggesting a crossing over from the Atlantic to the 
Pacific slope in western Panama were obtained. This crossing over 
is suggested by three species of characins; namely, Brycon obscurus, 
taken at El Valle, and Brycon .behreae and Roeboides guatemalensis, 
in the vicinity of Caldera. The specimens upon which Behre (1928, 
p. 318) based the Caldera record of the last-named species were not 
seen by me. The other two, described herein as new, are extremely 
closely related to Atlantic slope (Chagres River) forms, and rather 
remotely to species found east of El Valle. Bryconamericus zeteki 
from El Valle, here described as new, is very closely related to B. 
emperador, which occurs on both slopes in the vicinity of the Canal 
Zone, but apparently not at El Valle. B. zeteki, too, may have 
reached this locality from the Atlantic slope, as the indications are 
that the Pacific slope characins of central Panama have not reached 
El Valle. 

According to the most authentic information obtainable, the two 
streams sampled in El Valle, a small, flat area supposedly the crater 
of an extinct volcano, are both branches of the Anton River, a Pacific 
slope stream, though a small branch of the Rio Indio, a tributary of 
the Atlantic, cuts into El Valle. Evidently the streams of the 
opposite slopes approach each other closely in El Valle. Possibly 
with the aid of high water, or through volcanic action as suggested 
elsewhere, a transfer of fish from one slope to the other may have 
taken place here. Farther westward, where there is evidence of 
comparatively recent volcanic action, further transfers may have 
occurred. 

It is interesting that such common species of characins of the 
Pacific slope of central Panama as Brycon striatulus, Brycon argenteus 
and Roeboides occidentalis apparently do not occur in western Panama, 
and perhaps not even as far westward as El Valle, where an influx 
of Atlantic slope species apparently has taken place. The specimens 
listed as Brycon striatulus from western Panama by Behre (1928, 
p. 317) have been restudied and found to belong to an undescribed 
species here named B. behreae. 

It is surprising that the exceedingly abundant characin, Astyanax 
ruberrimus, of both slopes of central Panama, was also missing at 
El Valle, though it was common near there in streams toward the 
Canal Zone side of a high ridge. Neither has this species been taken 
farther westward. A related species, recorded as this one by me 
(1928, p. 83) was secured in certain volcanic lakes, near Volcan, 
Chiriqui. Several differences were found, however, upon comparison 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 223 

and careful study of specimens from central and western Panama. 
The Volcan material is apparently new and is named Astyanax 
kompi. 

It is interesting that in my investigations in the Chiriqui Viejo 
Basin no native fish was found above an elevation of about 5,000 feet. 
Only Brachyraphis terrabensis was found, at altitudes of about 4,800 
to 5,000 feet. Down to about 4,200 feet, below which no collections 
were made, Rhamdia rogersi and many Brachyraphis terrabensis 
were taken. Agonostomus was seen, but not captured. In lakes 
Gulnar and Grande, which supposedly occupy the craters of extinct 
volcanoes, situated at an elevation of about 4,500 feet, Brachyraphis 
terrabensis and Astyanax kompi were numerous, and Rivulus volcamis 
was common. The last-named, also, is described here as new. 

It might be supposed that the rainbow trout had eradicated the 
native species in the upper stretches of the Rio Chiriqui Viejo. 
However, in Puerto Rico, where no introductions had been made in 
most of the streams examined, the writer (1935) found few or no 
fishes above an elevation of 1,500 to 2,000 feet, the species apparently 
being unable to penetrate the colder water of the upper stretches of 
the streams. It seems probable that a similar situation prevails in 
the Rio Chiriqui Viejo. 

The relationship of the fishes of the Chagres Basin and opposing 
Pacific slope streams, including the Bayano, were discussed in the 
introduction to our earlier work. There is little to be added. As 
pointed out previously, the species of the opposite slopes in central 
Panama are very similar. Some differ in minor, but apparently 
constant, characters. Others remain identical. Yet it is undoubt- 
edly correct to say that the fishes of the opposite slopes of central 
Panama are more dissimilar; that is, they have "drifted" farther 
apart, morphologically, than the fishes of the Pacific slope of eastern 
Panama and the Atlantic slope of Colombia. In other words, the 
fishes of the Tuyra Basin and those of the Atrato and Magdalena 
basins are more closely related, morphologically, than the fishes of 
the Chagres Basin and the opposing Pacific slope streams. A greater 
difference exists, however, between the fishes of the Chagres and 
those of the Atrato and Magdalena. 

Although the number of identical species occurring in different 
streams is not an absolute criterion of the relationship of the faunas, 
yet it seems rather significant. Accordingly the following numbers are 
presented, in which the fresh and brackish water gobies with separate 
ventrals, that is, the Eleotridae, are omitted because they are not 



224 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

strictly fresh-water fishes. Several doubtful records of fishes of 
other families are also excluded. After these exclusions have been 
made, there remain records of 21 species common to both slopes of 
central Panama, and 37 that inhabit only one slope. Comprising 
the latter are 16 from the Atlantic and 21 from the Pacific slope. 

Breder (1927) discussed the relationship of the fishes of the Bayano 
and Tuyra basins. As no new collections have been made in these 
rivers Mr. Breder's remarks stand substantially as reported. There 
are listed in these pages 32 species common to the basins of these 
streams, as compared with 18 species common to the Bayano and 
the Chagres basins. Breder pointed out the apparently close 
approach of the upper branches of the Bayano and the Chucunaque, 
and the possibility of a recent connection. The rather large number 
of identical species seems to show that a comparatively recent 
passageway for fishes existed. 

The relationship of the fishes of the Tuyra and the Atrato basins 
was discussed briefly in our earlier work. Since that time Eigenmann 
(1920) has given it further attention. In the present paper 26 species 
are listed from the Tuyra, which Eigenmann (1922) also listed from 
the Atrato and the Magdalena. The close approach of the upper 
tributaries of the Atrato and the Tuyra was pointed out in our 
earlier work. That the Indians to the present time drag their 
wooden dugouts across the divide was confirmed recently by an eye- 
witness. It is not surprising, therefore, that a considerable number 
of species in the two streams are identical, or at least closely related. 
It is interesting that only 18 of the 57 species listed from the Tuyra 
Basin are recorded from the Pacific slope of Colombia. 

It has been stated elsewhere that the fishes of the Chagres Basin 
differ rather more widely from those of the Atrato and the Magdalena 
basins than from those of the Tuyra. In partial confirmation it may 
be stated that 12 identical species are listed from the Chagres and 
the Atrato and Magdalena basins, whereas 17 identical species are 
recorded from the Chagres and the Tuyra basins. 

The information gained since our earlier work was printed, then, 
seems to show more clearly that most of the fishes of eastern and 
central Panama are of South American origin. The principal route 
of migration apparently was from the Atlantic slope of Colombia to 
the Pacific slope of eastern and central Panama. The most probable 
route is from the Atrato to the Tuyra; from the Tuyra to the Bayano; 
and from the Bayano and neighboring coastal streams to the Chagres. 
The slight information suggesting a "re-recrossing " in western Panama 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 225 

has already been stated. The fishes of far western Panama, however, 
are chiefly Central American. 

I am pleased to quote from a letter by R. A. Terry, the geologist 
who has explored Panama extensively, findings that seem to be in 
agreement with the indicated connections of Atlantic and Pacific 
slope streams shown by the distribution and relationship of the 
fish faunas of various streams of Panama. In a sketch map Mr. 
Terry shows the close approach of the headwaters of the Tuyra and 
the Atrato rivers on the Panama-Colombia border. He says: "It 
seems likely that branches of the upper Tuyra have been pirated 
(cut into) by the Salaqui (an upper tributary of the Atrato), thus 
transferring Atrato fishes to the Tuyra .... Just when it took place 
I do not know, further than that it must have been subsequent to 
the late Pleistocene (or post-Pleistocene) elevation. 

"A similar favorable stream piracy occurs between the heads of 
the Chillibrillo and the Maria Prieta just east of the Canal Zone, 
where limestone sinks occur almost on the continental divide, which 
is quite flat. These sinks might conceivably be shifted from one 
drainage to the other by the development of solution channels 
irrespective of the normal erosive power of the streams to which 
they drain. 

"In the El Valle region the eruption which formed the El Valle 
volcanic crater with its surrounding walls must have been termi- 
nated earlier than the late Pleistocene, or post-Pleistocene time. I 
suspect that shifting of stream channels by this late vulcanism is 
responsible for the migration of species in this region, and also in the 
vicinity of Caldera, where the ejecta of the Chiriqui Volcano have 
obviously changed the drainage system of the region greatly." 

INTRODUCTION OF FISHES 

The first record of introduction which has been found, is con- 
tained in Mosquito Control in Panama, by J. A. Le Prince and A. J. 
Orenstein (1916, p. 185), where it is reported that Girardinus poecil- 
lodes (=Lebistes reticulatus) the "millions fish" or "guppy" was 
brought from Barbados. The date of introduction is not given, but 
in a recent letter Mr. Le Prince states that the fish were brought 
about 1910 or 1912. The few fish received were bred in captivity 
for a time; they multiplied rapidly; and batches were liberated in 
several places now included in Gatun Lake. As no specimens have 
been reported from Panama since the introduction was made, the 
species apparently failed to become established. It is highly prob- 



226 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

able that some of the native species of viviparous top minnows, 
especially Gambusia nicaraguensis, Brachyraphis episcopi, and 
Allogambusia tridentiger, are even more useful for mosquito control. 
Mr. Le Prince, who was chief- sanitary inspector for the Isthmian 
Commission from 1904 to 1914, knows of no other introductions of 
top minnows. 

Upon the request of the Canal Zone authorities, at least two ship- 
ments of young fish, one in 1917 and another in 1925, have been 
made. The first shipment consisted of "450 large mouth bass, 1,000 
catfish, and 800 sunfish." The second one contained "2,250 large 
mouth bass, 500 blue-gills and 500 crappies." The fish, according 
to a Canal Zone informant, were planted in Gatun Lake, at Gatun, 
immediately upon arrival. These plants apparently failed, as no 
specimens of the fish introduced were seen or taken during my visits 
in 1935 and 1937. The stray reports of the capture of bluegills and 
a crappie, such as was once reported in Fisheries Service Bulletin 
No. 182, 1925, may have resulted from misidentifications by the 
reporters. I was able to trace one such erroneous report. A certain 
Canal employe, who claimed that the bluegill had become established, 
without hesitancy identified Cichlasoma maculicauda as the bluegill, 
when specimens of this cichlid were placed before him. 

The only introduction that has been a success, to date, is that of 
the rainbow trout, introduced into the Rio Chiriqui Viejo in western 
Panama, in 1925, through a shipment of eggs. The writer spent 
several days on this river, in 1935, between an elevation of about 
4,500 and 7,000 feet. Above an altitude of about 5,000 feet the 
trout probably are as abundant as in any stream in the United 
States. At lower elevations the temperature is too high for trout. 
Trout-fishing in the high altitude, where the nights are always cool, 
if not cold, is giving enjoyable recreation to many Canal employees, 
as well as others, who visit there from time to time. An account of 
the status of this introduction, together with some records of tem- 
perature and foods utilized by the trout, was given by me (1935) 
in the Bulletin of the Pan-American Union. Inadvertently the 
number of eggs planted was stated as 2,500 in the article cited, 
whereas 25,000 eggs were actually sent. 

No doubt rainbow trout would thrive in other mountain streams 
of western Panama, where the maximum temperature is 70 F. or 
less. It has been reported that an introduction in the vicinity of 
Boquete, presumably in the upper tributaries of the Rio Chiriqui, 
is beginning to yield returns. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 227 

At present the lakes of the Canal support few food and game 
fishes. The few that provide sport and food are mostly migrants 
from the sea, the most important one being the tarpon, as pointed 
out in my recent (1937) paper. There is no commercial fishery, 
worthy of the name. It does seem that such a fine large body of 
water as Gatun Lake, having an area of 196 square miles and a 
shore line about 1,100 miles long, should be more productive. The 
newly created Madden Lake, with an area of 18 square miles, 
apparently should support food and game fishes after the dense 
vegetation covered has decayed in part and settled. 

The temperature of the lakes seemingly would not preclude some 
of the warm-water fishes of the United States, which have been 
introduced successfully in Puerto Rico, Cuba, and elsewhere. Accord- 
ing to Canal records furnished through the courtesy of Mr. R. Z. 
Kirkpatrick, the minimum surface temperature of Gatun Lake dur- 
ing any one month from 1919 to 1936 inclusive, based on two daily 
readings, one at 8:00 A.M. and another at 2:00 P.M., was 80.9 F., 
which occurred during January, 1928. The maximum for readings, 
taken at the same time and place, was 86.2, reached in June, 1930. 
The average yearly temperature, based on the same records, has 
fluctuated from 82.6 in 1927 to 84.8 in 1930. The indications are 
that the temperature of the recently formed Madden Lake will be 
only a few degrees lower than that of Gatun Lake. The cold of the 
northern winters and the heat of the summers are only very slightly 
reflected as far south as Panama. 

The native river fishes of the vicinity do not seem to have become 
numerous in the lakes, exclusive of the small characin ("sardina"), 
Astyanax ruberrimus, which is exceedingly abundant. As this fish 
reaches a length of only about 75 mm. it is too small to be of direct 
value as food for man. If this fish could be utilized as food for 
larger fishes it might still be valuable. It is not evident just yet how 
that can be done without sacrificing the top minnows, which must 
be preserved, as shown subsequently. 

In the endeavor to make the fresh waters of the Canal productive, 
the first step apparently should be an investigation of these 
waters and their animal and plant life, including a careful study of 
the life habits (especially breeding) of the native fishes. Introduc- 
tions should be considered only after a careful study of the indige- 
nous fishes has been made. 

Three native species of fresh-water fishes would seem worthy of 
special study; namely, the two "sabalo pepons," Brycon chagrensis 



228 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

and B. petrosus, and the "mojarra," Cichlasoma maculicauda. 
Although the sabalo pepons grow much larger, reaching a length of 
two feet or so, the mojarra, which resembles the bluegill superficially, 
and reaches a similar size, probably is the most promising. The last- 
mentioned species is already fairly common in Gatun and Miraflores 
lakes. Its food and game qualities, however, seem largely unknown. 

Great care should be exercised as to introductions of food and 
game fishes, because the population of top minnows (Poeciliidae) 
in the lakes must be maintained for the purpose of mosquito and 
malaria control. Certainly such highly predatory fishes as the large 
mouth bass and the pikes and pickerels should not be introduced. 
Less destructive species, as for example, the bluegill sunfish and the 
bullhead catfish, might be considered. The introduction of carp has 
been suggested by Colonel H. C. Pilsbury, Chief Health Officer, 
who expressed the hope that it might become numerous enough to 
thin the plant growth and thereby aid the top minnows in destroying 
larval mosquitoes. The carp, of course, is not highly regarded as a 
food fish, and scarcely ranks as a game fish, though it can be caught 
on a hook with the use of vegetable baits. Once hooked, it puts up 
a good fight. It seems only remotely probable, however, that the 
carp would become abundant enough to make appreciable inroads 
on the very extensive plant growth present. 

It may be remarked that it seems useless to attempt the further 
introduction of fry or fingerlings, as earlier attempts failed completely. 
It would seem necessary to introduce fish too large to be managed by 
the exceedingly abundant and highly predatory "sardina," Astyanax 
ruberrimus. Whether the introduced fishes could breed, even if 
they themselves survived, is problematical. It might be necessary 
to maintain hatcheries to keep the lakes stocked, which would be 
expensive if virtually no reproduction took place naturally. It is 
evident, then, from the foregoing that the establishment and the 
maintenance of food fishes in the artificial lakes of the Canal is a 
complicated matter which should receive further study. 

NEW AND ABANDONED LOCALITIES 
As many changes in local nomenclature have taken place in the 
Canal Zone, and in the Chagres Basin beyond the Canal Zone, since 
1911 and 1912 when our previous collections were made, a brief 
explanation seems desirable. Several towns listed as collecting 
stations in our earlier work no longer exist. Some of these were 
abandoned because the ground on which they were situated was 



1938 FFESH-WATER FISHES OF PANAMA HILDEBRAND 229 

flooded; others were not needed after the construction of the Canal 
had been completed; and a few became rather inaccessible through 
the flooding of the Canal and the relocation of the Panama Railroad. 
Names of a few new localities also appear in the present report. 

As an aid to those who may use the earlier, as well as the present 
work, the changes are listed in the order they occur or occurred from 
the Atlantic terminus of the Canal southward. The changes in the 
Chagres Basin east of the Canal Zone also are discussed. 

Toro Point, situated across Limon Bay from Colon and Cristobal, 
is now generally called Fort Sherman. 

Mindi, formerly situated a short distance south of Mount Hope, 
no longer exists. 

New Gatun has been replaced in approximately the same locality 
by Fort Wm. D. Davis. Gatun itself remains situated in its former 
location; namely, at the place where the Chagres River was dammed 
to form Gatun Lake. 

Monte Lirio, formerly situated on the Rio Gatun, is now on an 
island in Gatun Lake, the river being almost wholly included in 
the lake. 

Agua Clara, situated on the Rio Trinidad, a large tributary of 
the Rio Chagres west of the route of the Canal, was flooded and 
abandoned. 

Bohio, situated on the route of the Canal, about 15 miles south 
of Gatun, came within the flooded area and had to be abandoned. 

Barro Colorado Island is one of the new localities where collec- 
tions were made during the present investigation. Formerly a high 
hill, it is now the largest island in Gatun Lake. It has been made 
a wild life preserve, and upon it is situated the laboratory of the 
Institute for Research in Tropical America. This island lies west- 
ward across Gatun Lake from the railway station, Frijoles. 

Tabernilla, Gorgona and Bas Obispo, all along the direct route 
of the Canal and the Chagres River, were flooded and abandoned. 

Gamboa, situated near Bas Obispo, was not used as a collecting 
station in 1911 and 1912. It is now one of the important stations on 
the Panama Railroad. In 1935 when collections were made in the 
upper end of Gatun Lake, it served as a collecting station. Accord- 
ingly, the name appears several times in the present catalogue. 

Beyond Gamboa, and on the west side of the then proposed Canal, 
were situated the important towns, Empire and Culebra. The latter, 
at the summit of the divide, was the headquarters of the Isthmian 



230 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Canal Commission during the construction of the Canal. Though 
these places are shown on current maps they have virtually been 
abandoned, having became rather inacessible when the Panama 
Railroad was relocated on the east side of the Canal. 

Summit is one of the new localities appearing in the present work. 
As its name indicates, it is situated at the summit of the divide, on the 
relocated railroad. It is the seat of -a botanical experiment station. 

Miraflores Lake and the Rio Cocoli appear as new localities in 
the present work. The lake is a small body of water situated on the 
Pacific side of the divide between Pedro Miguel and Miraflores 
Locks. It was formed by damming the now virtually destroyed Rio 
Grande. Its chief tributary is the Rio Cocoli. Sometimes, with the 
operation of Miraflores Locks, the lower flight of which is at sea level, 
the main body of this lake becomes slightly brackish, but not so 
much so as to exclude fresh-water fishes. This lake is connected 
with Culebra (or Gaillard) Cut and Gatun Lake through the Pedro 
Miguel Locks. 

Alhajuela, an important collecting station during our earlier 
investigations, was at that time situated on the banks of the Chagres 
River, about a day's journey by cayuca upstream (eastward) from 
Gamboa, outside the Canal Zone. It served as a hydrographic 
station. It has now been abandoned, but the main building still 
stands, and is situated at the head of Gatun Lake, just below the 
recently constructed Madden Dam. 

San Juan, formerly on the banks of the Rio Boqueron, a short 
distance above the union of this stream with the Chagres, is now 
situated on the newly formed Madden Lake, having been moved 
from its former location, which was flooded. Specimens listed in 
the present paper from the "mouth of the Boqueron" were taken 
some distance upstream from the former location of San Juan, where 
this river now empties into Madden Lake. 

Most of the stretches of the upper Chagres and the Rio Indio, 
in which collections were made in 1911, now are included in or at 
least affected by Madden Lake. 

ACKNOWLEDGMENTS 

Most excellent cooperation, direct help, and innumerable courtesies 
were extended during the investigations by more individuals than 
space will permit me to mention. I feel deeply grateful to all. The 
investigations were first suggested by Dr. Herbert C. Clark, director 
of the Gorgas Memorial Laboratory, Panama City. Without his 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 231 

constant cooperation, including financial aid, the work could not 
have been done. I am deeply indebted, also, to Dr. A. 0. Foster, 
of the Gorgas Memorial Laboratory, for much help and the collection 
of many specimens. Thanks, in fact, are due the entire staff of the 
laboratory, all of whom cooperated most excellently. 

The officers of the Panama Canal gave valuable aid. Among 
these must be mentioned Colonel C. S. Ridley, Governor; Colonel 
Glen E. Edgerton, Engineer of Maintenance; Major W. D. Styer, 
Assistant Engineer of Maintenance; Mr. R. Z. Kirkpatrick, Chief 
of Surveys; Mr. E. D. Still well, Superintendent of Locks; and Messrs. 
H. M. Thomas and J. C. Myrick, Assistant Superintendents of Locks. 

Among others who cooperated, and to whom I am deeply in- 
debted, are Mr. W. H. W. Komp, of the United States Public Health 
Service; Mr. J. B. Shropshire, malariologist with the United States 
Army; Mr. Fred Whaler, the ardent angler and student of Panama 
fishes; Mr. R. G. Lewis, business man of Panama City; Professor 
James Zetek, the well-known Canal Zone biologist; Mr. George 0. 
Lee and Miss Elinor D. Robinson, of the Canal Zone schools; and 
Messrs. R. B. Potter, S. A. Venable, Carl G. Brown, and R. A. 
Cauthers. Finally I must thank Alfred C. Weed, Curator of Fishes, 
Field Museum, for critically reading and editing the manuscript. 

NEW SPECIES DESCRIBED 

Gephyrocharax whaleri Brycon obscurus 

Astyanax kompi Rivulus volcanus 

Bryconamericus zeteki Rivulus montium 

Brycon behreae Euleptoeleolris (gen. nov.) clarki 

Euleptoeleotris shropshirei 

CATALOGUE OF SPECIES 

Family PIMELODIDAE. Naked Central and 
South American Catfishes 

The genera appearing under Pimelodidae herein were placed 
under Siluridae in our earlier (1916) work. During recent years 
there has been a tendency to follow Regan (1911), who divided 
Siluridae into several families. The family Pimelodidae, as defined 
in part by Regan, is characterized by the separate gill membranes, 
which are free from the isthmus; 3 pairs of barbels (1 pair maxillary, 
2 pairs mandibular, and no nasal barbels); anterior and posterior 
nostrils far apart; 6-rayed ventrals; and a well-developed adipose. 

The key to the genera under the family Siluridae in our earlier 
publication may be followed, except that the second part relating to 



232 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

the humeral process, under c and cc, should be transposed (see under 
Pimelodus). 

Rhamdia Bleeker. 

On the basis of records by Behre (1928) and myself (1928), and 
some additional specimens obtained recently, three species of this 
genus not included in our earlier work are added to the fauna of 
Panama. These three species are all Central American forms that 
have invaded western Panama. 

The chief diagnostic characters of this genus are the weak, flexible 
dorsal spine; the short occipital process which does not reach the 
dorsal plate; the free orbital margin; and the rather long adipose fin 
which is adnate to the back. 

The species are imperfectly understood. For this reason no key 
is offered, though characters that are supposedly diagnostic are 
mentioned in the accounts. 

Rhamdia wagneri (Giinther). 

Pimelodus wagneri Gunther, Trans. Zool. Soc. Lond., 1868, p. 474 Atlantic 

and Pacific rivers of Panama. 
Rhamdia wagneri Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 240, 1916. 

This common species was secured during the recent investigations 
in a stream flowing through Chillibrillo Cave, at Barro Colorado 
Island, and in a small creek flowing into an abandoned reservoir near 
Gatun. Since our earlier publication (1916) it has been recorded 
from several places in the Rio Chucunaque Basin by Breder (1927, 
p. 101), and from streams of both slopes of extreme western Panama 
by Behre (1928, p. 307). 

The very long adipose fin, which begins in advance of the tips 
of the dorsal rays if deflexed, and which is much longer than the head ; 
the very long maxillary barbel, which often reaches beyond the 
ventral; and the well-forked caudal aid in identifying this species. 

Not much in evidence during the dry season, but when the wet 
season comes in April and May it schools. The writer has seen a 
dozen or more individuals swimming leisurely at the surface in quiet 
places among grass in the swollen streams, where they could be 
captured easily. It is evident that this fish does not find darkness 
objectionable, as it was common in a small stream in Chillibrillo Cave. 

Attains a length of about 400 mm. (12 inches), and is said to be a 
food fish of good quality. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 233 

This species, as now understood, ranges from Costa Rica, south- 
ward into Colombia, possibly to Ecuador, and is common on both 
slopes of Panama, and in Colombia. 

Rhamdia godmani (Gunther). 

Pimelodus godmani Gunther, Cat. Fish. Brit. Mus., 5, p. 124, 1864 Vera 
Cruz, Mexico; Rio Motagua, Guatemala. 

Included on the basis of a record by Behre (1928, p. 306) founded 
on specimens taken in the Rio Cricamola, on the Atlantic slope of 
extreme western Panama. R. godmani has not been reported from 
Costa Rica. Dr. Behre found her specimens to be somewhat inter- 
mediate in some respects between wagneri and underwoodi, and not 
entirely in conformity with godmani. I have not seen these speci- 
mens, but on the basis of distribution a new species is suggested, as 
godmani was recorded only from Vera Cruz, and Yucatan, Mexico; 
from the Rios Motagua and Usumacinta, Guatemala; and from 
Belize prior to Dr. Behre's record. Dr. Behre mentions a "Pacific 
coast" record from Honduras, and refers to godmani as "a north 
Pacific-coast form," but I have not been able to find a record of its 
occurrence on the Pacific slope. It seems somewhat significant that 
Meek (1914) did not record it from Costa Rica, and that the species 
was not recognized among the specimens from Costa Rica studied by 
me (1930). 

This species seems to be characterized by the rather well-forked 
caudal fin; the short occipital process, which extends less than half 
the distance from its base to the origin of the dorsal ; and the moder- 
ately long adipose, which is longer than in rogersi, but shorter than in 
wagneri, being about 1^ times the length of the head. 

Rhamdia underwoodi Regan. 

Rhamdia underwoodi Regan, Biol. Cent. Amer., Pisces, p. 135, pi. 23, fig. 4, 
1907 Juan Vinas, Costa Rica. 

Included in the fauna of Panama on the basis of specimens taken 
by Behre (1928, p. 308) in the Rio Cricamola, on the Atlantic slope 
of extreme western Panama. Recorded also from both slopes of 
Costa Rica. 

This species is characterized by the rather deeply notched (not 
forked) caudal, the very short occipital process, which reaches only 
about one-fifth to one-sixth the distance from its base to the origin 
of the dorsal; the rather short adipose, which is not much longer 
than the head; and the short maxillary barbel, which reaches only 
about to the tips of the pectoral. 



234 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Rhamdia rogersi (Regan). 

Pimelodus rogersi Regan, Ann. Mag. Nat. Hist., (7), 19, p. 259, 1907 
Irazu, Costa Rica. 

Taken with hook and line in Miller's Spring, flowing into a tribu- 
tary of the Rio Chiriqui Viejo, Pacific slope of extreme western 
Panama, from whence it was already recorded by Hildebrand (1928, 
p. 82). 

Differs prominently from R. wagneri in the much shorter adipose 
fin, which begins far behind the tips of the dorsal rays, and is little 
if any longer than the head; in the much shorter maxillary barbel, 
which fails to reach the tips of the pectorals; and in the unforked 
caudal fin, which has only a slight notch. 

It was originally described from Irazu, Costa Rica. It has been 
recorded from both slopes of Costa Rica; and from the Pacific slope 
of extreme western Panama, on the basis of specimens already 
mentioned. 

Pimelodus Lacepede. 

This genus differs prominently from Pimelodella in the much 
shorter and broader humeral process. Unfortunately, in the key to 
the genera in our earlier work (1916, p. 239) this well-marked dif- 
ference between this genus and Pimelodella was transposed. When 
using that key, "humeral process broad, not spine-like," under cc, 
should be exchanged with "humeral process spine-like" under c. 
This difference is correctly stated in the descriptions of the genera. 
A single species is known from Panama. 

Pimelodus clarias punctatus (Meek and Hildebrand). 

Megalonema punctatum Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 77, 1913 Rio Tuyra at Marrigante. 
Pimelodus clarias punctatus Meek and Hildebrand, Field Mus. Nat. Hist., 

Zool. Ser., 10, p. 241, 1916. 

This subspecies is known only from the Tuyra Basin. Since the 
publication of our earlier work (1916), Breder (1927, p. 103) has 
recorded many specimens from the Rio Chucunaque, having found 
it nearly as common as Rhamdia wagneri. 

Pimelodella Eigenmann and Eigenmann. 

This genus is recognized by the stiff pungent dorsal spine; the 
deeply forked caudal; the long occipital process, which reaches the 
dorsal plate; the narrow spine-like humeral process, which reaches 
nearly opposite mid-length of the pectoral spine; and the free orbital 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 235 

margin. In the key to the genera in our earlier work (1916) the 
differences in the humeral processes of this genus and Pimelodus were 
inadvertently transposed (see under the genus Pimelodus). 

Pimelodella chagresi (Steindachner). 

Pimelodus (Pseudorhamdia) chagresi Steindachner, Sitzber. Akad. Wiss. 
Wien, 74, p. 584, 1876 Rio Chagres and tributaries. 

Pimelodella chagresi Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 242, 1916. 

This common catfish was secured in Miraflores Lake and in the 
Rio Cocoli a short distance from the lake, and also in the Rio Cabra 
on the Panama City-Chepo Road. It is common on both slopes of 
central Panama and also in the Tuyra Basin of eastern Panama. 
Since our earlier work was published it was obtained by Breder (1927, 
p. 102) at several places in the Rio Chucunaque and tributaries, and 
through a record by Behre (1928, p. 308), based on specimens secured 
in the Rio Chiriqui del Tire, Pacific slope of western Panama, the 
range was extended considerably westward from the Canal Zone. 
The range as now understood extends from western Panama into 
Colombia, where it occurs in the Atrato and Magdalena basins. It is 
definitely known from both slopes only in central Panama. 

This species should be handled with care, as it secretes the most 
painful poison of any catfish ever handled by the writer, who suffered 
severely for a half hour or so after being "finned," and who saw a 
native roll on the ground in agony after a like experience. For- 
tunately, no bad after effects were noticed. 

This fish does not grow large enough to be of value as food, as 
ib apparently seldom reaches a length as great as 150 mm. (6 inches). 

Trachycorystes amblops (Meek and Hildebrand). 

Felichthys amblops Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 77, 1913 Rio Tuyra at Marrigante. 
Trachycorystes amblops Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 243, 1916. 

Three small specimens, respectively 43, 54, and 63 mm. long, 
were taken in a swamp at the La Jagua Hunting Club, situated on the 
Pacific slope, about 15 miles east of Panama City. This species 
was known heretofore only from the lower part of the Rio Tuyra 
Basin from specimens reported in our earlier work (1916, p. 243) and 
by Breder (1927, p. 104). 

The specimens at hand agree well with the Rio Tuyra material. 
The sides are marked with dark longitudinally elongate spots, which 
are almost united along middle of side in the 54 mm. specimen, form- 



236 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

ing a lateral band. The description in our earlier work stated that 
the dorsal spine had "barbels" on the anterior margin. "Barbs" 
obviously should be. substituted for "barbels." 

The following proportions and counts are based on the three small 
specimens at hand: Head 3.4 to 3.9; depth 3.6 to 3.7; D. I, 5 or 6; 
A. 18 to 20. Snout 4 to 4.4 in head; eye 5.6 to 6.3; interorbital 
1.4 to 1.8; caudal peduncle 2.5 to 2.8. Pectoral spine 3.9 to 4.7 in 
standard length. 

Ageneiosus Lace"pede. 

Maxillary barbels only are present in this genus; the orbital 
margin is not free; the occipital process is joined to the dorsal plate, 
and the humeral process is wanting. The single species of this genus 
known from Panama has been taken there only in the Tuyra Basin. 

Ageneiosus caucanus Steindachner. 

Ageneiosus caucanus Steindachner, Denkschr. Akad. Wiss. Wien, 41, p. 61, 
pi. 6, figs. 1, 2, 1880 Rio Cauca; Meek and Hildebrand, Field Mus. Nat. 
Hist., Zool. Ser., 10, p. 245, 1916. 

This fish, known in Panama only from the Tuyra Basin, has been 
reported, since the publication of our earlier work, by Breder (1927, 
p. 104) from the Rio Chucunaque at the island below Yavisa. 
According to Eigenmann (1922, p. 50) this species occurs also in the 
Atrato and Magdalena basins. 

Family LORICARIIDAE. Mailed Catfishes 
This family of South American Nematognathi ranges northward 
into eastern and central Panama, the northernmost record for Pan- 
ama being "Veragua," presumably meaning the State of Veraguas 
(see under Plecostomus plecostomus panamensis} . No representatives 
of the family have been found in extreme western Panama, that is, 
in the states of Chiriqui and Bocas del Toro, where Dr. Ellinor H. 
Behre and others have collected. However, there is a record in the 
National Museum of a Plecostomus plecostomus taken in the Quebrada 
de India, Colorado de Goto, Costa Rica. The species are widely dis- 
tributed in South America. Charles M. Breder, Jr. (1925 and 1927) 
working in the Chucunaque Basin of eastern Panama, added many 
records from that river system, and described a new species. 

We are indebted to Mr. Breder also for information in regard to 
the food of these fishes. In general the intestinal tract is long and 
convoluted, as typical of herbivorous fishes. It is much longer, how- 
ever, in members of the subfamily Plecostominae, including the 
genera Plecostomus, Chaetostomus, Ancistrus, Lasiancistrus, and 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 237 

Leptoancistrus, than in the members of the subfamily Loricariinae, 
which includes among the Panama fauna the genera Loricaria and 
Sturisoma. The food in all the species consisted of a flocculent 
material, composed largely of algae and mud, which is probably 
obtained, by scraping and sucking, from the rocks and pebbles 
among which the species commonly live. 

Plecostomus plecostomus panamensis Eigenmann. 

Plecostomus plecostomus panamensis Eigenmann, Mem. Carnegie Mus., 9, 
No. 1, p. 69, 1922 Chagres River at Monte Lirio and Gatun. 

This fish, like Ancistrus chagresi, commonly lives in streams 
among the rocks. It seemed to be more numerous than the relative 
just mentioned during our work in 1911 and 1912. Only one speci- 
men, 345 mm. long, was taken during the recent investigation. This 
one was secured in Miraflores Lake at the mouth of the Rio Cocoli. 
This capture does not show, however, that the species is living under 
lake conditions. It evidently was not taken oftener in 1935 and 
1937 because little collecting was done in rocky streams, its usual 
habitat. 

The very long convoluted intestine is generally filled with a slimy 
mass, apparently mostly of vegetable origin. Breder (1927, p. 108) 
stated that the intestines were "all packed with soft flocculent mud, 
algae, et cetera." It clings closely to stones. In 1912, while collecting 
in the upper Tuyra Basin, the fish could be seen clinging to stones, 
and we succeeded in capturing a few specimens by lifting stones with 
fish attached, from the water. The fish clung to the stones so tightly 
with their sucking mouth and flat chest and abdomen, that it took 
some little power to remove them. 

This species is listed as P. plecostomus in our earlier work (1916, 
p. 247). However, Eigenmann (1922, p. 69) found the Panama 
specimens to differ from typical P. plecostomus of South America in 
having the occipital plate bordered by several (3 or more) small 
plates instead of 1 or 2 larger ones. Accordingly, Eigenmann recog- 
nized the Panama specimens as representatives of a new subspecies, 
for which he offered the name panamensis. 

To the synonymy in our earlier work should be added Plecostomus 
bicirrhosus Giinther (1866, p. 477), reported from "Pacific and 
Atlantic coast rivers of Panama," and Plecostomus guacari Regan 
(1907, p. 111). 

Although Eigenmann (1922, p. 75) recognized Chaetostomus 
aspidolepis Gunther (1866, p. 603; and 1868, p. 477), reported from 
"Veragua" (presumably meaning the State of Veraguas of western 



238 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Panama) as distinct, placing it in the genus Hemiancistrus, I shall 
regard it as synonymous with P. plecostomus panamensis for the 
reasons stated: Only Gunther's description is available to us, which 
was based on a skin (presumably dry, though not so stated) 12*4 
inches long. Owing to the removal of the soft parts, and drying, it 
probably was somewhat distorted. The apparently larger inter- 
opercular spines, which evidently led Eigenmann to place it in the 
genus Hemiancistrus (a genus otherwise not found in Panama), may 
well have seemed longer because of shrinkage. The other difference 
that apparently might be of some importance is the supposedly 
narrower head. This apparent difference also might have resulted 
from shrinkage. The proportionate length of the head, however, 
agrees with Canal Zone specimens. It probably is significant, also, 
that the number of fin rays and scutes given agrees with specimens 
that are undoubtedly P. plecostomus panamensis. 

No Loricariidae were taken in the extreme western states of 
Panama, namely, Chiriqui and Bocas del Toro, by Dr. Ellinor H. 
Behre, and others who collected there. Giinther's record, "Vera- 
gua," therefore, remains as the westernmost one of the family in 
Panama. However, there is a record of a specimen in the United 
States National Museum, identified by Dr. George S. Myers, from 
the Quebrada de India, a Pacific slope stream, a tributary of the 
Rio Colorado, which is a tributary of the Rio Goto. Upon inquiry 
from Professor Manuel Valerio, the collector, I am informed that 
this spcies is known locally as "Arrisuaca," and that it is common 
enough to be used as food. 

Though P. plecostomus ranges south to Uruguay, the subspecies 
panamensis, as now understood, is found in Panama, from Vera- 
guas(?) to the Rio Tuyra Basin in Darien. In central Panama it 
occurs on both slopes. It is not reported from the Bayano, though it 
very probably occurs there. The single specimen from Costa Rica, 
mentioned in the preceding paragraph, very probably belongs to 
this subspecies. 

Chaetostomus fischeri Steindachner. 

Chaetostomus fischeri Steindachner, Denkschr. Akad. Wiss. Wien, 41, p. 162, 
pi. 4, 1879 Rio Mamoni, near Chepo; Meek and Hildebrand, Field Mus. 
Nat. Hist., Zool. Ser., 10, p. 249, 1916. 

This species was not taken during the recent investigation prob- 
ably because virtually no collecting was done in suitable places in 
streams. Since our earlier work (1916, p. 249) was published, Breder 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 239 

(1927, p. 109) has reported it from the Chucunaque Basin from the 
"Rio Chico and Sucubti in clear water." 

This species is recorded from both slopes of central Panama and 
from the Pacific slope of eastern Panama. Presumably it is rare in 
the Chagres Basin, as we took only one specimen there during our 
intensive collecting in 1911 and 1912. According to Eigenmann 
(1922, p. 82) this species occurs on both slopes of Colombia and 
southward into Ecuador. 

Ancistrus chagresi Eigenmann and Eigenmann. 

Ancistrus chagresi Eigenmann and Eigenmann, Proc. Calif. Acad. Sci., (2), 2, 
p. 47, 1889 Rio Chagres; Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 251, 1916. 

Eight specimens, ranging in length from 37 to 235 mm., were 
seined along Madden Dam Road, in a creek formerly a tributary 
of the Rio Chagres and now flowing into Gatun Lake. As no speci- 
mens were secured in Gatun or Miraflores Lake, it is not known 
whether this typical river fish is living in these artificial lakes, though 
it was present in some parts of the Chagres River, now included in 
Gatun Lake, before the canal was completed. This species com- 
monly lives in streams on rocky bottom, clinging closely to rocks 
with its sucking mouth and flat chest and abdomen. 

Policeman S. A. Venable of the Canal Zone, who is interested in 
"pet fish," kept small individuals of this species in his aquaria, when 
observed in 1935, to act as scavangers. This fish is sluggish in the 
aquarium, and as in nature it stays chiefly on the bottom. 

A specimen, 75 mm. long, when observed in Mr. Venable's 
aquarium, was dark green with pale round spots on the upper surface 
of the head and body. 

This species is known only from central Panama where it has been 
taken on both slopes. 

Ancistrus spinosus Meek and Hildebrand. 

Ancistrus spinosus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 252, 1916 Rio Calobre, tributary to Rio Bayano. 

This species was not taken during the recent investigation. It 
was described by us (1916, p. 252) from only two specimens, one 
from the Bayano and the other from the Tuyra Basin. Since that 
time Breder (1927, p. 109) has reported it from five specimens taken 
in the Chucunaque Basin from the "Rio Chico, the Sucubti and the 
latter's confluent in clear water in company with Chaetostomus." 



240 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Lasiancistrus planiceps (Meek and Hildebrand). 

Ancistrus planiceps Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 79, 1913 Rio Tuyra, Boca de Cupe; Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 253, pi. 10, 1916. 

This species, described from specimens from the Rio Tuyra and 
its upper tributaries, has been recorded also from eight specimens by 
Breder (1927, p. 108) from the "Rio Chucunaque, above the mouth 
of the Rio Chico, at the Indian village; Rio Sucubti, at the Indian 
village and the creek near it, below the falls." 

Leptoancistrus canensis (Meek and Hildebrand). 

Acanthicus canensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 80, 1913 Rio Cana, Cana, Panama. 
Leptoancistrus canensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 254, pi. 11, 1916. 

Known only from the type material collected in small mountain 
streams near Cana in the upper Tuyra Basin. 

Loricaria uracantha Kner and Steindachner. 

Loricaria uracantha Kner and Steindachner, Abhand. Bayer. Akad. Wiss. 
Miinchen, 10, p. 56, pi. 6, 1866 New Granada; Rio Chagres; Meek and 
Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 256, 1916. 

A single small specimen, 55 mm. long, was seined along the 
Madden Dam Road, in a creek formerly a tributary to the Rio 
Chagres and now flowing into Gatun Lake. 

We found this species very common in streams in shallow water 
with swift current and a sandy or gravelly bottom in the Chagres 
Basin in 1911 and 1912. It evidently was not secured oftener during 
my recent work because very little collecting was done in suitable 
places. 

The species has been recorded from "Atlantic and Pacific rivers 
of Panama," but we have taken it only in the Chagres Basin, and are 
inclined to doubt the Pacific slope record. 

Loricaria latiura Eigenmann and Vance. 

Loricaria filamentosa latiura Eigenmann and Vance, in Eigenmann, Indiana 
Univ. Studies, No. 16, p. 13, 1912 Boca de Certegai, Colombia; Meek 
and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 257, 1916. 

This species appears under the trinomial, L. filamentosa latiura, 
in our earlier work. However, Eigenmann (1922, p. 91) considered 
latiura sufficiently different from filamentosa to give it full specific rank. 

As understood by Eigenmann, L. latiura occurs in the Tuyra and 
Atrato basins. This is one of several species that are common 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 241 

to the Tuyra on the Pacific slope of Panama and the Atrato on the 
Atlantic slope of Colombia. 

Loricaria variegata Steindachner. 

Loricaria variegata Steindachner, Denkschr. Akad. Wiss. Wien, 41, p. 163, pi. 
3, 1879 Rio Mamoni, near Chepo; Meek and Hildebrand, Field Mus. 
Nat. Hist., Zool. Ser., 10, p. 258, 1916. 

Nine specimens, ranging in length from 16 to 210 mm., were 
reported from the Chucunaque Basin by Breder (1927, p. 112). 
Previously the species had been recorded in Panama from the "Rio 
Mamoni, near Chepo" (type locality) and from the Rio Tuyra. Mr. 
Breder states: "The present series varies beyond the limits of the 
Meek and Hildebrand, 1916, description as follows: The cross-row 
of scutes between the pectorals is obsolescent in some specimens, 
being merely represented by a few scattered asperities on the other- 
wise smooth skin. In some cases the plates anterior to the vent are 
scarcely enlarged and the caudal varies from strongly emarginate to 
forked. The longest caudal filament (99 mm.) is on a male of 199 mm., 
as measured from the tip of the second, not produced, caudal ray." 

According to Eigenmann (1922, p. 93), it occurs in the Atlantic 
drainage of Colombia in the Atrato and Magdalena basins. The 
extremes of the range, then, are the Rio Mamoni on the Pacific slope 
of Panama and the Rio Magdalena on the Atlantic slope of Colombia. 
It is not reported from the Pacific slope of Colombia. 

Loricaria capetensis Meek and Hildebrand. 

Loricaria capetensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 80, 1913 Rio Capeti, tributary to the Tuyra; p. 259, pi. 12, 1916. 

Known only from the two original specimens from the Tuyra 
Basin. Breder (1927, p. Ill) has questioned its validity (see under 
L. fimbriata}. 

Loricaria fimbriata Eigenmann and Vance. 

Loricaria fimbriata Eigenmann and Vance, Indiana Univ. Studies, No. 16, 
p. 12, 1912 Boca de Certegai and Bernal Creek, Colombia; Meek and 
Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 260, 1916. 

Previously known from Panama only from 4 specimens, 50 to 80 
mm. long, taken in the Rio Capeti (tributary of the Tuyra), by Meek 
and Hildebrand (1916, p. 260), and reported by Breder (1927, p. Ill) 
from a specimen 54 mm. long, from the Rio Tupisa, tributary 
of the Chucunaque. Breder has suggested that three closely 
related species, namely, fimbriata and capetensis from the Tuyra 
Basin, and seminuda from Girardot on the Magdelena River in 



242 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Colombia, should be reduced to one. These nominal species are 
supposedly distinguished chiefly by the differences in the develop- 
ment of the abdominal scutes. Since the degree of development of 
the scutes almost certainly depends largely upon age and size of the 
fish, Mr. Breder is probably correct. However, not enough speci- 
mens are available (none of seminuda) to determine definitely that 
no differences exist in fully mature specimens, wherein differences 
could not be ascribed to age. 

Loricaria altipinnis Breder. 

Loricaria altipinnis Breder, Amer. Mus. Nat. Hist., Nov., No. 180, p. 1, fig. 2, 
A and B, 1925 Rio Chico, Darien, Panama; Bull. Amer. Mus. Nat. 
Hist., 57, p. 110, fig. 4, 1927. 

According to Breder (1925, p. 3), this fish may be distinguished 
from L. uracantha, the most closely related species in Panama, "by 
the anterior rays of the dorsal reaching beyond those of the posterior 
ones when depressed, instead of being co-terminous; the distance 
from the origin of dorsal to longest deflexed ray being equal to the 
distance from the tip of snout to posterior margin of occipital plate 
instead of to the middle of that plate; the distance from origin of 
anal to longest deflexed ray being equal to the distance from the 
snout to a point well past the orbital notch instead of to its posterior 
margin. The smaller examples differ greatly from young L. ura- 
cantha of the same size, as those closely resemble the larger examples 
of that form, instead of differing from them, as previously noted for 
the present species." 

Mr. Breder gave the following counts and proportions, based 
on the type and on 11 paratypes, ranging in length from 38 to 163 
mm: Head 4.2 to 4.6; depth 10 to 12.5; lateral scutes 28 or 29. 
Snout 2.1 to 2.4 in head; eye 5 to 8; interorbital 4 to 5.1; pectoral 
1.3 to 1.4. Abdominal plates 3 to 7. The color is described in the 
type (standard length 154 mm.) as "brownish above, lighter below, 
the back crossed by six darker bars, the first on nape, indistinct, the 
second at base of dorsal, the rest approximately equidistant on the 
remainder of the body. All fins yellowish with dark spots, anal with 
fewer and lighter ones." 

The smaller paratypes, ranging in length from 38 to 94 mm., are 
described as similar in color, but darker, tending to be "Vandyke 
brown" instead of tan. 

This species is known only from the type material of which Breder 
said (1927, p. 110): "Known only from the Rio Chucunaque and its 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 243 

confluents .... Most frequently taken in pools in the dry beds of 
evaporating side streams." 

Sturisoma Swainson. 

Sturisoma Swainson, Nat. Hist. Fish., Amph. Kept., 2, p. 304, 1839 type 
Loricaria rostrata Spix. 

The above name has replaced Oxyloricaria Bleeker (1863) used 
in our earlier work (1916, p. 261), on the basis of priority. 

Sturisoma panamensis (Eigenmann and Eigenmann). 

Loricaria panamensis Eigenmann and Eigenmann, Proc. Calif. Acad. Sci., 

(2), 2, p. 34, 1889 Panama. 
Oxyloricaria panamensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 261, 1916. 

Breder (1927, p. 113) recorded 22 specimens from the Chucunaque 
Basin. Meek and Hildebrand (1916, p. 261) had reported the species 
common in the Rio Tuyra, but rare in the Bayano (type locality). 

The general range as given by Eigenmann (1922, p. 94) extends 
from the Bayano and Tuyra basins (Pacific slope) in Panama, 
through both slopes of Colombia to western Eucador. 

Sturisoma citurensis (Meek and Hildebrand). 

Oxyloricaria citurensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 82, 1913 Rio Cupe, Cituro; p. 262, pi. 13, 1916. 

Breder (1927, p. 113) recorded seven examples from the Chucuna- 
que Basin. We (1916, p. 262) reported it abundant in the Rio Tuyra, 
but rare in the Bayano. Its distribution, so far as known, is limited 
to the basins of the Bayano and Tuyra of the Pacific slope of Panama. 

Family CALLICHTHYIDAE 
Hoplosternum punctatum Meek and Hildebrand. 

Hoplosternum punctatum Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 264, pis. 14 and 15, 1916 Rio Marte Arnade, near Panama City. 

Described in our earlier work from four specimens taken in the 
Rio Marte Arnade, about six miles east of Panama City. Since that 
time Breder (1927, p. 107) has reported 183 specimens, 30 to 66 mm. 
long, from the Rio Chucunaque, near Yavisa, where the species 
seems to be common, though not seen by us in the Rio Tuyra. There 
is now at hand one additional specimen, 60 mm. long, seined in a 
swamp at the La Jagua Hunting Club, about 15 miles east of Pan- 
ama City. This specimen conforms well with the type material 
from the Rio Marte Arnade, except that the origin of the dorsal 
seems rather farther back, being equidistant from tip of snout and 



244 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

the beginning of adipose, wherein it conforms more nearly with 
Breder's specimens from the Tuyra drainage. 

It is known only from the specimens mentioned in the foregoing 
paragraph, taken in a Pacific coastal stream and swamp not far from 
Panama City and in the Tuyra Basin. A closely related species, 
H. magdaknae, occurs in the Atlantic drainage in Colombia. 

Family ASTROBLEPIDAE 

The above name is substituted for Cyclopidae in our earlier work 
(1916, p. 265) for reasons stated in the account of the genus Astro- 
blepus, A single genus with one species is known from Panama. 

Astroblepus Humboldt. 

Astroblepus Humboldt (in Humboldt and Bonpland), Recueil 
d' observations de zoologie et d'anatomie compared faites dans 
l'0ce"an Atlantique, dans Tint^rieur du nouveau continent et dans 
la Her du Sud, pendant les annees 1799, 1800, 1801, 1802, et 1803, 
13, 48 pages, 7 pis.; Pt. 4, 1805, Me"moire sur I'Eremophilus et 
1' Astroblepus deux nouveaux genres de 1'ordre des Apodes, par 
M. de Humboldt, p. 37 (type Astroblepus grixalvii). 1 The accounts 
of Astroblepus and A. grixalvii appear also in the Philosophical 
Magazine (London), without reference to the earlier work, 24, 
February to May, 1806, Art. 59, pp. 329 to 333, Memoir on the 
Eremophilus and Astroblepus, two new Genera of the Order Apodes. 
By M. de Humboldt. The account of Astroblepus is given on page 
331 and a drawing of A. grixalvii appears on pi. 7, which has the 
same number as the one in the earlier work published in Paris. 

The name given above, following Eigenmann (1922, p. 51), 
replaces Cydopium in our earlier work (1916, p. 265). Eigenmann 
stated: "The mountain cat-fishes, hitherto known chiefly under the 
names Cyclopium and Arges, are considered here under the above 
generic name. Astroblepus was described by Humboldt as lacking 
ventrals, and has not been recognized since the publication of the 
original description, based on 'pescado negro' of Popayan. 

"Posada, a Colombian naturalist (cf. his Estudios Cientificos, 
1909), made a special effort to secure such a fish lacking ventrals, 
but did not find any, although many specimens were examined. 

1 The book cited above is volume 13 of a general work consisting of 24 volumes 
published in Paris from 1805 to 1837, entitled, Voyage aux regions equinoxiales 
du nouveau continent, fait au 1799-1804, etc., par Frederich Heinrich Humboldt 
et A. J. A. Bonpland. A second edition of the volume on Zoology, etc. (13), was 
published in Paris in 1811, wherein an account of Astroblepus appears in volume 1, 
page 19. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 245 

"Likewise in our collections, numbering hundreds of individuals, 
no specimens lacking ventrals are to be found. It seems, therefore, 
that the lack of ventrals in the figure of Humboldt is due to a mistake 
of the artist. Humboldt's name must stand as the earliest designa- 
tion of these fishes." 

The acceptance of this earlier name necessitates also the change 
of the family name from Cyclopidae to Astroblepidae. 

Astroblepus longifilis (Steindachner). 

Arges longifilis Steindachner, Denkschr. Akad. Wiss. Wien, 46, p. 19, pi. 5, 
fig. 3, 1882 Rio Huambo, Rio Totora, northern Peru. 

Eigenmann (1922, p. 54) synonymized Cyclopium pirrense Meek 
and Hildebrand (1916, p. 265) with the above. Breder (1927, p. 105) 
reported seven specimens from the "Rio Sucubti, in the creek at the 
Indian village, above the falls," Chucunaque Basin. In Panama 
this species has been reported only from the Rio Tuyra drainage. 
According to Eigenmann (1922, p. 54) this species ranges from the 
Rio Tuyra in eastern Panama to Peru, occurring in some places on 
both slopes. 

Family PYGIDIIDAE 

Prior to the work of Behre (1928) a single species of this family 
was known from Panama, which was reported only from the Rio 
Tuyra drainage. 

Pygidium septentrionale Behre. 

Pygidium septentrionale Behre, Ann. Carnegie Mus., 18, p. 309, pi. 18, 1928 
Quebrada Solao, tributary to the Rio Chiriquf del Tire, near Caldera, 
western Panama. 

No specimens have been seen by me. I quote from the original 
description. 

"Head as broad as long; distance from chin to nearest point of 
gill, half the width of head. Length of head 6 to nearly 7 in length to 
base of caudal. Diameter of eye 3 in interocular width. Maxillary 
barbels reaching to origin of pectorals or shorter. Teeth conical, 
sharply pointed. Dorsal, caudal, and anal fins truncate. Pectoral 
filament short. Origin of dorsal above or a little in advance of vent 
and equidistant from tip of caudal and preopercle; distance from 
caudal nearly 2 in its distance from snout. Last dorsal ray over anal, 
but not over last. Origin of ventrals nearer tip of pectoral filament 
than caudal. Color slate inclining to brownish, mottled, especially 
below. Belly also dark." 



246 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

This species is known from 12 specimens, ranging in length from 
69 to 110 mm., secured by Dr. Behre in the Rio Chiriqui del Tire, 
in the vicinity of Caldera, at an altitude of about 4,000 feet. 

Apparently the head is shorter and broader than that of striatum, 
being at least as broad as long, and its length is contained 6 to nearly 7 
times in the standard length. The origin of the anal is farther for- 
ward with respect to the dorsal, as its origin is in advance of the last 
ray of the dorsal, whereas in striatum the origin of this fin is under or 
behind the last ray of the dorsal. P. septentrionale seems to be plainer 
in color, being slate to brownish and mottled, especially below. 
P. striatum is light olive and has a dark lateral band, and sometimes 
one additional one above and below the one along the middle of the 
side. These bands are sometimes more or less broken up into spots. 
The larger individuals have black spots on the back and sometimes 
on the lower parts also. 

Pygidium striatum Meek and Hildebrand. 

Pygidium striatum Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 78, 1913; p. 266, 1916 Rio Cana, Cana, Panama. 

This was the only species of the genus and family known from 
Panama, until Behre (1928, p. 309) described P. septentrionale from 
western Panama, where she also took one specimen of P. striatum. 
Previously, the last-mentioned species was known only from the type 
material from a small mountain stream at Cana in the upper part 
of the Rio Tuyra Basin. Dr. Behre took the fish at an elevation of 
about 4,000 feet. 

According to Eigenmann (1922, p. 64) this species occurs also on 
both slopes of the mountains of Colombia. Although the species has 
not been taken in central Panama, where the elevation probably is 
too low, the general range apparently extends from western Panama 
into Colombia. 

Family CHARACINIDAE 

The members of this family are very numerous, ranging from the 
Rio Grande in Texas to Argentina and Peru. They are most abund- 
ant, however, in the equatorial parts of South America and become 
comparatively few north of the Isthmus of Panama. Some of the 
species grow large and are of value as food fishes, but many of them 
are small. The shape of the body varies from short and deep and 
strongly compressed, to long and slender or even pike-like. Scales 
are present on the body, but not on the head; the upper jaw anteriorly 
is formed by the premaxillaries, and laterally by the maxillaries; teeth 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 247 

various, often strong, and rarely wanting (as in Curimatus)', dorsal 
fin small, without spines; an adipose fin is usually present (wanting 
in Hoplias). 

In Panama the species have various names, as shown subse- 
quently. In general the large species (Brycori) are called "sabalo," 
that is, herring, and the small species are mostly called "sardina," that 
is, sardines. 

One genus, Characidium, has been added to the fauna of Panama 
since the publication of our earlier (1916) general work. A descrip- 
tion is offered subsequently. 

Characins are decidedly fewer in western than in central and 
eastern Panama. Dr. Behre (1928) secured only five genera, namely, 
Brycon, Astyanax, Bryconamericus, Hyphessobrycon, and Roeboides 
(including nine species), in western Panama, whereas these and 14 
others (including 32 species) are known from the central and eastern 
sections of the republic. It seems evident, then, that many of the 
genera have their northernmost limit of distribution in central and 
eastern Panama. In fact, four genera, namely, Apareiodon, Phana- 
goniates, Hemibrycon, and Characidium, have been found no farther 
north (west) than the Tuyra Basin. 

Curimatus Oken. 

The members of this genus are widely distributed, ranging from 
Panama to Argentina and Peru. One species is known from Panama. 
The genus is characterized by the elongate robust body; the small 
mouth, which is without lips and without teeth ; the complete lateral 
line; well-developed adipose fin; and the very long intestine. 

Curimatus magdalenae Steindachner. 

Curimatus magdalenae Steindachner, Denkschr. Akad. Wiss. Wien, 29, p. 50, 
1878 Rio Magdalena; Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 269, 1916. 

Specimens were secured in 1935 and 1937 on the Pacific slope east 
of Panama City at the La Jagua Hunting Club, in the Rio Tapia, 
and in the Rio Cabra. 

Breder (1927, p. 113) recorded specimens from several places in 
the Chucunaque Basin. 

Known from the Pacific slope of Panama, from the Rio Chorrera 
to the Rio Tuyra; also from the Atlantic slope of Colombia (Atrato 
and Magdalena basins) and southward into Venezuela. Although 
it has been taken by us on both sides of the Canal Zone, we have not 
found it within the Zone. This fish is herbivorous, as suggested by 



248 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

the very long intestine. It usually lives in quiet shallow water, which 
at times is very warm. 

Apareiodon dariensis (Meek and Hildebrand). 

Parodon dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 83, 1913 Rio Cupe, tributary of the Tuyra. 
Apareiodon dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 271, pi. 17, 1916. 

Originally described from three specimens taken in the Rio Cupe, 
tributary to the Rio Tuyra. Breder .(1927, p. 114) recorded a fourth 
specimen from the Rio Chucunaque from slightly above the mouth 
of the Rio Chiati. He, also, secured a second species of the genus, 
a description of which appears herewith. 

A. dariensis remains known only from the Tuyra Basin. 
Apareiodon compressus Breder. 

Apareiodon compresstts Breder, Amer. Mus. Nat. Hist., Nov., No. 180, p. 4, 
figs. 3, 4, 1925; Bull. Amer. Mus. Nat. Hist., 57, p. 115, figs. 5, 6, 1927 
Rio Tuquesa, Chucunaque Basin, Darien, Panama. 

This species is known from a single specimen, 23 mm. long, which 
has not been seen by me. The following description is condensed 
after Breder. 

Head 3.2, depth 3.9, D. 11, A. 9, scales 36. Body elongate, some- 
what compressed; dorsal profile convex; snout bluntly pointed, not 
much in advance of mouth, 4.4 in head; eye 3; interorbital 3.1; 
mouth very small, inferior; lower jaw toothless; upper jaw with large, 
close-set overlapping teeth, wide at tips, with slightly rounded 
pectinate margins; lateral line straight; dorsal fin inserted in advance 
of ventrals, its origin about midway between snout and base of caudal ; 
anal fin small, shorter than head, its origin nearer to base of caudal 
than to base of ventrals; ventral fins broad, with 9 rays, reaching 
beyond vent; pectorals broad, with 14 rays, not reaching ventrals. 

Color only slightly darker above than below; sides with a dark 
band, following lateral line; base of caudal with an elongate black 
spot; nape with a dark triangular area, connected with a median dark 
line extending to dorsal fin. Dorsal and caudal slightly dusky; other 
fins plain. 

This species differs prominently from the only other one (darien- 
sis) of the genus known from Panama, in the much shorter and 
less strongly projecting snout, and in color. In dariensis the snout 
is pointed, much in advance of the mouth, and is contained in the 
head 2.8 to 3 times. The color is dark brown above, the sides have 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 249 

2 more or less broken black bands, and the dorsal and caudal lobes 
are prominently barred with black. 

Characidium Reinhardt. 

Small or minute fishes, elongate and generally subcylindrical in 
form. The jaws are provided with a single series of conical or tri- 
cuspid teeth; no frontal fontanel, but a small circular occipital one; 
lateral line complete; gill membranes free from the isthmus; adipose 
fin present. 

Known from Panama from a single species, described by Breder 
(1925, p. 5). Therefore, it is not included in the general work on the 
fresh-water fishes of Panama by Meek and Hildebrand (1916). 
The species of the genus are described by Eigenmann (1922, p. 121) as 
living like and resembling Etheostoma (the darters) of North America. 

Characidium marshi Breder. 

Characidium marshi Breder, Amer. Mus. Nat. Hist., Nov., No. 180, p. 5, fig. 5, 
1925; Bull. Amer. Mus. Nat. Hist., 57, p. 115, 1927 Rio Sucubti, Chu- 
cunaque Basin, Darien, Panama. 

This species is known only from the type material, consisting of 
eleven specimens ranging in length from 15 to 44 mm. The specimens 
have not been seen by me. The following description is condensed 
after Breder. 

Head 3.3 to 3.8; depth 3.9 to 4.7; D. 11; A. 7 to 9; scales 31 to 35, 
in front of dorsal 10 or 11, across peduncle 5 to 7. Body elongate, 
subcylindrical; dorsal profile convex; snout bluntly pointed, 4 to 4.3 
in head; eye 3.9 to 4.7; mouth subterminal; maxillary reaching eye; 
teeth conical in upper jaw, weakly tricuspid in lower jaw; lateral 
line weakly developed, complete, slightly decurved; dorsal fin 
inserted in advance of ventrals, about equidistant from anterior 
margin of eye and tip of adipose; adipose over last anal rays; pec- 
torals reaching ventrals, the outer rays thickened, the fins equal to 
length of head. 

Color dark above, paler below; side with a dark band crossed by 
7 vertically elongate spots, the last one extending somewhat on middle 
caudal rays, encompassing a small black dot. Dorsal dusky, crossed 
by a dark bar on basal half; other fins plain dusky. 

This is the only species of the genus known from Panama. 

Phanagoniates macrolepis (Meek and Hildebrand). 

Roeboides macrolepis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 84, 1913 Rio Cupe, Tuyra Basin. 
Phanagoniates macrolepis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 272, 1916. 



250 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Since the publication of our earlier (1916) work, Breder has 
recorded this fish from the Rio Chico and the Rio Sucubti in the 
Chucunaque Basin. 

This species is known from the Tuyra Basin in Panama and the 
Atrato in Colombia. In the Tuyra it seems to be rather rare. 

Compsura Eigenmann. 

The minute fishes of this genus (the Panama representative 
apparently being less than 50 mm. in length) differ from related 
forms in the peculiarly enlarged scales on the base of the lower lobe 
of the caudal fin in the male. The genus is further characterized by 
having a single series of multicuspid teeth in each jaw, and by having 
an incomplete lateral line, present on only about 5 to 13 scales. A 
conspicuous black caudal spot is present in the single species occur- 
ring in Panama waters. 

Compsura gorgonae (Evermann and Goldsborough). 

Cheirodon gorgonae Evermann and Goldsborough, Proc. Biol. Soc. Wash., 22, 

p. 99, figs. 1,3, 1909 Gorgona, Canal Zone. 
Compsura gorgonae Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 274, 1916. 

This is the smallest of the characins ("sardinas") occurring in the 
local waters. No individuals exceeding a length of 40 mm. have been 
found. Although it occurs on both slopes of central Panama, it does 
not seem to be numerous there. Specimens were secured in 1935 
and 1937 in an abandoned reservoir at Mount Hope; in Gatun Lake 
at Gatun and Barro Colorado Island; in Madden Lake; in a creek 
tributary to Gatun Lake on Madden Dam Road; in the Rio Cocoli, 
tributary to Miraflores Lake; in the Rio Cabra; and in a swamp 
at the La Jagua Hunting Club. The three localities last named 
are on the Pacific slope. As this species occurs naturally on both 
slopes of Panama, it is not possible to determine from the specimens 
collected whether it uses the Pedro Miguel Locks as a passageway 
between Gatun Lake (Culebra Cut) and Miraflores Lake. 

The rather short deep compressed body, the incomplete lateral 
line (present on only about 5 to 13 scales) and the large black spot 
on the base of the caudal fin are recognition marks. The single series 
of multicuspid teeth in each jaw, and peculiarly enlarged scales on 
the base of the lower lobe of the caudal fin are other distinguishing 
characters. The following proportions and counts are based on 
seven specimens unless otherwise stated : 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 251 

Head 3.75 to 4.3; depth 2.6 to 3; D. 10; A. 17 to 20; P. 10 to 12; 
scales 4 or 530 to 343 or 4; vertebrae 12 or 13+17 or 18 (two 
specimens examined). Snout 4.8 to 6 in head; eye 2.7 to 3.2; inter- 
orbital 3.2 to 4. Distance from snout to dorsal 1.8 to 2 in standard 
length; base of anal 4 to 4.9; pectoral 4.6 to 5. 

This fish was recorded from the upper Rio Chucunaque by Breder 
(1927, p. 117). Its range, so far as known to date, is limited to both 
slopes of central Panama, and the Tuyra Basin in eastern Panama. 

Pseudocheirodon Meek and Hildebrand. 

This genus, of which a single species is known, is characterized by 
the compressed body with elevated back; the broad second sub- 
orbital which covers nearly the entire cheek; the single series of pre- 
maxillary and mandibular teeth with expanded tips that overlap 
more or less; the incomplete lateral line, usually present on only 8 to 
12 scales; and the normally scaled base of caudal and non-protruding 
interhaemal spines in both sexes. 

Pseudocheirodon affinis Meek and Hildebrand. 

Pseudocheirodon affinis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 275, pi. 18, 1916. 

In 1935 and 1937 specimens were collected in an abandoned 
reservoir at Mount Hope; in the upper end of Gatun Lake (Chagres 
River), not far from Madden Dam; in Miraflores Lake, in swamps 
at the La Jagua Hunting Club; and in several small coastal streams 
on the Pacific slope, including the Pacora, the Cabra, and a small 
stream near Campana. As this species was common to both slopes 
before the Canal was opened, it cannot be determined from the collec- 
tions whether it uses the Pedro Miguel Locks as a passageway. 

P. affinis seldom exceeds a length of 55 mm. It is most readily 
recognized by the single series of teeth on the premaxillaries; the 
incomplete lateral line, which is usually present on only 8 to 12 scales; 
the normally scaled base of caudal, and non-protruding interhaemal 
spines in both sexes; and the large black caudal spot, followed by a 
whitish area on both lobes of the caudal fin. 

The following counts and proportions are based on seven speci- 
mens (unless otherwise stated), ranging in length from 27 to 50 mm.: 

Head 3.6 to 4.3; depth 2.6 to 2.9; D. 10 or 11; A. 22 or 23; P. 10 
or 11; scales 5 or 6 30 to 33-5; vertebrae 12 or 13 + 16 or 17 (two 
specimens examined). Distance from snout to dorsal 1.8 to 2 in 
standard length; base of anal 3.4 to 4; pectoral 4.5 to 5.3. Snout 
5.1 to 5.6 in head ; eye 2.8 to 3.2 ; interorbital 2.8 to 3.5. Premaxillary 



252 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

teeth in a single series, consisting of 10 to 12 multicuspid teeth ex- 
panded at tips, with none of the cusps especially enlarged; maxillary 
with 2 low multicuspid teeth; mandible with 10 or 12 broad multi- 
cuspid teeth with expanded tips that overlap more or less. 

Breder (1927, p. 118), who reported many specimens from several 
places in the Chucunaque Basin, remarks concerning their occurrence, 
"Taken only above the head of tide, becoming more abundant as the 
headwaters were approached, generally being found in large schools 
in quiet and comparatively deep pools." 

This species is known from both slopes of central Panama and the 
Tuyra Basin of eastern Panama. 

Gephyrocharax Eigenmann. 

This genus is recognized by the strongly compressed body; the 
strongly rounded ventral outline; the long anal (consisting of 29 to 
32 rays in Panama species) ; the posteriorly inserted dorsal fin, which 
has its origin behind that of the anal; the presence of two series of 
teeth on the premaxillaries; the broad second suborbital covering 
the entire cheek; and the peculiar "spur" formed by the lower free 
fulcra of the caudal in the male. 

The differences among the three species taken in Panama are 
shown in the accompanying parallel. 

DISTINGUISHING CHARACTERS OF PANAMA SPECIES 

OF GEPHYROCHARAX 

atricaudata intermedius whaleri 

Profile from snout to oc- Profile as in atricaudata. Profile from tip of snout 

ciput slightly convex; a to occiput straight, no 

definite off-set at mouth. off-set at mouth. 

Gape and lower lip notably Gape as in atricaudata. Gape and lower lip on level 

below dorsal outline of with upper lip; entering 

head; not entering into into the nearly straight 

the general profile of dorsal profile of head, 
head. 

Lower lip thin. Lower lip as in atricau- Lower lip broader and more 

data. or less fleshy. 

Pectoral fin long, gener- Pectoral shorter, gener- Pectoral long, as in atricau- 
ally reaching to or beyond ally failing to reach data, 3.6 to 4.1 in stand- 
middle of ventral, 3.7 to middle of ventral, 4 to ard length, average in 21 
4.25 in standard length, 4.5 in length, average specimens 3.78. 
average in 21 specimens in 19 specimens 4.25. 
3.9. 

Dorsal fin low, failing to Dorsal fin as in atricau- Dorsal fin high, reaching 

reach adipose by 1 or 2 data. to or beyond origin of 

rows of scales if deflexed. adipose if deflexed. 

Caudal spot not followed Caudal spot followed by Color as in intermedius. 
by a whitish area on each a whitish area on each 
lobe of the fin. Outer lobe of the fin. Outer 
rays of caudal black. rays of caudal not 
black. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 253 
Gephyrocharax atricaudata (Meek and Hildebrand). 

Gephyrocharax atricaudata Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 68, 1912 Rio Frijoles, Canal Zone; p. 277, 1916. 

Many specimens were collected in 1935 and 1937. A particularly 
fine lot was taken in the Rio Cocoli, a short distance from Miraflores 
Lake, but none in the lake itself. Some of these specimens are larger 
than any previously seen, ranging upward to 65 mm. in length. The 
species was secured also in Gatun Lake near Gatun ; a short distance 
below Madden Dam; in the present mouth of the Rio Boqueron, 
above Madden Lake; in a small stream, formerly a tributary of the 
Chagres, on Madden Dam Road; in an abandoned reservoir at 
Mount Hope; in a swamp at the La Jagua Hunting Club; and in the 
Rio Pacora and the Rio Cabra on the Panama City-Chepo Road. 

G. atricaudata occurs on both slopes of central Panama, but is 
replaced by two other species of the genus in the coastal streams 
between Campana and La Venta. As this fish naturally inhabits 
both slopes of central Panama it is impossible to determine from 
specimens whether it uses Pedro Miguel Locks (wherein it was not 
found) as a passageway, though that is not improbable. 

This species was quite accurately described by Meek and Hilde- 
brand (1916, p. 277), though no mention was made of the seemingly 
somewhat longer pectoral fin than in intermedius, with which it is 
very closely related in structure. The following proportions and 
counts are based on eight specimens, unless otherwise stated, ranging 
in length from 43 to 65 mm. : 

Head 4.2 to 4.5; depth 2.8 to 3; D. 9; A. 31 or 32; P. 10; scales 
7-38 to 41-5; vertebrae 10 or 11+24 or 25 (three specimens examined). 
Snout 3.8 to 4.6 in head; eye 3 to 3.4; interorbital 2.7 to 3.1. Dis- 
tance from snout to dorsal 1.5 to 1.7 in standard length; base of anal 
2.8 to 3; pectoral 3.7 to 4.25 (21 specimens examined). 

Breder (1927, p. 125), who reported this species from several 
places in the Chucunaque Basin, found considerable variation in 
color, showing some intergradation with G. intermedius. No inter- 
gradation seems to exist among the material from central Panama. 
A difference in the proportionate length of the pectoral fins in the 
two species is shown in the parallel on page 252. 

G. atricaudata is common in the Chagres Basin, and on the Pacific 
slope from the Canal Zone eastward to the Tuyra Basin. 

Gephyrocharax intermedius Meek and Hildebrand. 

Gephyrocharax intermedius Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 278, 1916 Rio Chame. 



254 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

This species was described from the Rio Chame, where at that 
time (1911) G. whaleri was not secured. On March 10, 1937, while 
en route from Balboa to La Venta several stops were made for the 
purpose of collecting specimens in a half dozen or more small coastal 
streams crossing the National Highway between Campana and La 
Venta. The specimens from the different streams were not kept as 
separate collections. Of this species 23 were taken. Whether these 
specimens are all or in part from the Rio Chame, the type locality, 
cannot be stated. Neither is it known whether any of the new species, 
whaleri, herein described, were taken in the Rio Chame, as the species 
was not recognized in the field. 

The original description (Meek and Hildebrand, 1916, p. 278) of 
this species is essentially correct. However, it was not pointed out 
that the pectoral fins apparently are slightly shorter than in atri- 
caudata. Nor was it stated that the caudal spot is followed by a 
whitish area on each lobe of the fin. Unless otherwise stated the 
following proportions and counts are based on six specimens taken 
March 10, 1937: 

Head 4 to 4.3; depth 3.1 to 3.4; D. 9; A. 29 to 31; P. 9 or 10; 
scales 7-36 to 40-5; vertebrae 12+22 (one specimen examined). 
Snout 4.3 to 4.7 in head; eye 2.8 to 3.5; interorbital 2.6 to 3.2; dis- 
tance from snout to dorsal 1.6 in standard length; base of anal 2.8 to 
3.1; pectoral 4 to 4.5 (19 specimens examined). 

This fish inhabits the Rio Chame and probably neighboring 
coastal streams. 

Gephyrocharax whaleri sp. nov. 

Type from Rio Chame or a near-by stream, Pacific slope, 
Panama. No. 106513 United States National Museum. Total 
length 53 mm., standard length 40 mm. 

Description of the Type. Head 4.2; depth 3.1; D. 9; A. 32 (includ- 
ing 3 undivided rays); P. 11; scales 6-35-5. 

Body strongly compressed; the ventral outline very convex 
anteriorly, the dorsal profile straight and nearly horizontal from 
snout to occiput, gently convex posterior to occiput; snout shorter 
than eye, 4.1 in head; eye 3; interorbital 2.7; mouth strongly oblique, 
superior, the lower lip in advance of the upper one, entering into the 
general dorsal profile; maxillary ascending almost vertically close in 
front of eye, scarcely extending beyond anterior margin of orbit; 
lower lip rather broad and fleshy; premaxillary teeth in 2 series, the 
outer series incomplete and smaller than inner series; maxillary with 



1938 



FRESH-WATER FISHES OF PANAMA HILDEBRAND 



255 



2 small teeth; mandible with a single series of teeth, enlarged on 
anterior part of jaw with abruptly smaller ones on each side; gill 
rakers very short, mere points, 12 on lower limb of first arch; lateral 
line strongly decurved; scales moderate, the series only fairly regular; 
dorsal fin inserted posteriorly, equidistant from base of caudal and 
shoulder spot, distance from snout to dorsal 1.6 in standard length, 
the fin high with longest rays reaching adipose if deflexed; adipose 
over base of last rays of anal; caudal fin rather deeply forked; anal 
fin long, its origin fully an eye's diameter in advance of dorsal, its 
base 3 in standard length; ventrals moderate, reaching origin of anal; 




FIG. 2. Gephyrocharax whaleri sp. nov. Type, male, 53 mm. long. (From 
drawing by Louella E. Cable.) 

pectorals long, reaching somewhat beyond mid-length of ventrals, 
3.6 in standard length. 

Color greenish with silvery luster above, plain silvery below. 
Base of caudal with a prominent spot, followed by a whitish area, 
the black not extending on fin; a prominent vertically elongate 
shoulder spot present, extending nearly from the nape to behind base 
of pectoral ; fins plain colorless except for dusky points. 

Variations noticed in the paratypes are as follows: Head 3.75 to 
4.2; depth 3 to 3.2; A. 30 to 32 (including undivided rays); P. 10 
or 11; scales 6 or 7-35 to 38-5, before dorsal 17 to 20; vertebrae 
10 or 11+23 or 24 (three specimens examined). Snout 3.7 to 4.4 
in head; eye 2.8 to 3.4; interorbital 2.7 to 3.2. Distance from snout 
to dorsal 1.5 to 1.6 in standard length; base of anal 2.8 to 3; pectoral 
3.6 to 4.1 (21 specimens measured). 



256 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

The teeth are seen with difficulty without removing the jaws. 
Those in the upper jaw are in 2 series. The outer series is irregular 
and consists of 2 to 4 small tricuspid teeth on each side, with none in 
front of the 2 anterior (middle) teeth in second row. The second 
series is regular and the teeth are larger, with 4 or 5 teeth, each with 
3 to 5 cusps. Maxillary anteriorly with 2 very small tricuspid teeth. 
Mandible with 4 enlarged teeth on each side, followed by abruptly 
smaller ones. The enlarged teeth with 3 to 5 cusps, the middle cusp 
long and pointed. 

This species is represented in the collection by 50 specimens 
(including 23 males), ranging in length from 26 to 65 mm. These 
specimens are probably not all from one stream, as collections of fish 
were made in the Rio Chame and several smaller near-by coastal 
streams crossing the National Highway between Campana and La 
Venta. The several collections were not kept separate. 

This species agrees in color with intermedius, its nearest relative 
inhabiting the Rio Chame and probably other near-by streams. 
It differs from that species in the more nearly vertical mouth and 
thicker lower lip, which extends upward and enters into the straight 
dorsal profile of the head, whereas the lower lip in intermedius is 
lower than the upper one (as in atricaudata) , causing a decided break 
at the mouth in the general dorsal outline of the head. The thickened 
lower lip seems to be normal in G. whaleri, and has not been noticed 
in any of the many specimens of the other species of the genus 
examined, though in some other genera (Astyanax and Brycon- 
americus) of characins it does not seem to have any specific signifi- 
cance. The dorsal fin is notably higher (in both sexes) in whaleri 
than in the other local species of the genus, reaching to or a little 
beyond the origin of the adipose if deflexed, whereas in intermedius 
and atricaudata it fails to reach the adipose by 1 or 2 rows of scales. 
The specific differences among the three local species of Gephyro- 
charax shown in the accompanying parallel. 

I take pleasure in naming this species for my friend, Fred Whaler 
of Balboa, Canal Zone, who is an ardent angler as well as a student 
of fishes, and who rendered valuable assistance when the specimens 
were taken. 

Astyanax Baird and Girard. SARDINAS DE MONTANA. 

This species of this genus are small, compressed, rather deep- 
bodied fishes, the depth generally being contained, more than 2 times 
in the length to the base of caudal. The teeth in the premaxillaries 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 257 

are in 2 even rows, each row with 8 teeth in Panama species. The 
lower jaw has strong teeth (8 in Panama species) anteriorly, followed 
on each side by abruptly smaller ones. The maxillary has a few (2 
in Panama species) small teeth at its juncture with the premaxillary, 
or none. The second suborbital is rather narrow, not coming in 
contact with the lower limb of the preopercle, and it leaves a small 
naked triangular area at its juncture with the first suborbital. The 
lateral line is complete, and scales (all normal) do not extend far on 
the base of the caudal. The vertebrae in Panama species are 14+17 
or 18. Five species are known from Panama, one of them being new 
and herein described. 

Astyanax fasciatus (Cuvier). 

Chalceus fasciatus Cuvier, Mem. Mus. Paris, 5, p. 352, 1819 Brazil. 
Astyanax fasciatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 280, 1916. 

Specimens recently collected in central Panama, as well as those 
collected there and in eastern Panama by us in 1911 and 1912, differ 
prominently from specimens of the extremely abundant A. ruber- 
rimus in the absence of a black caudal spot. A. fasciatus also differs, 
so far as Panama material at hand is concerned, in being slightly 
deeper, in having a larger number of longitudinal rows of scales, and 
in reaching a somewhat larger size. Both species vary considerably 
in depth, causing the proportional measurements to overlap. An 
average difference exists, however, as in 26 specimens of A. fasciatus 
measured the range of the depth in standard length is 2.2 to 2.7, 
and the average 2.42. In 67 specimens of ruberrimus the range is 2.25 
to 3.1, and the average 2.66. A. fasciatus apparently nearly always 
has 8 rows of scales between the lateral line and the base of the first 
dorsal ray, and 7 between the lateral line and the base of the ventral. 
In 27 specimens examined two specimens differ, one having 7 rows 
above the lateral line, and another having 6 rows below it. In 30 
specimens of ruberrimus constantly 7 rows above the lateral line 
and 5 or 6 (usually 6) below it were counted. Specimens of 
fasciatus up to 150 mm. in length were taken, but none of ruberrimus 
exceeding 110 mm. 

Breder (1927, p. 122) found it difficult to separate his specimens 
from the Rio Chucunaque into two species and expressed doubt 
concerning the validity of fasciatus and ruberrimus. Eigenmann 
(1921, p. 306) placed the Panama specimens, identified by Meek and 
Hildebrand (1916, p. 280), as fasciatus, in the subspecies aeneus, 
which according to his key falls into the group having a dusky or 



258 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

black band extending to the end of the middle rays of the caudal fin. 
No such band is present in any of our Panama specimens. Behre 
(1928, p. 319) recorded A. aeneus costaricensis Meek from extreme 
western Panama (Atlantic slope). This subspecies apparently is a 
synonym of A. fasciatus aeneus as understood by Eigenmann. I 
am obliged to regard the identity of the Panama material from the 
Pacific slope with that of the Atlantic slope of western Panama and 
Costa Rica as very doubtful. 

Specimens were collected in 1935 and 1937 at the La Jagua 
Hunting Club, in the Rio Pacora and the Rio Cabra, and in other small 
coastal streams along the Panama City-Chepo Highway. One fine 
specimen, 107 mm. long, was taken in a creek, formerly tributary to 
the Rio Chagres, now flowing into Gatun Lake, not far from Madden 
Dam. As this species was not taken in the Atlantic drainage during 
the extensive collecting done on the Canal Zone and vicinity in 1911 
and 1912, before the opening of the Canal, it seems probable that it 
has "migrated" through Culebra Cut from the Rio Grande Basin 
of the Pacific slope. 

This species and its various subspecies or varieties, as now under- 
stood, range from Mexico through Panama and Colombia to Brazil. 

Astyanax ruberrimus Eigenmann. 

Astyanax ruberrimus Eigenmann, Indiana Univ. Studies, No. 18, p. 25, 1913 
Istmina, Atlantic slope, Colombia; Meek and Hildebrand, Field Mus. 
Nat. Hist., Zool. Ser., 10, p. 281, 1916. 

The relationship of this very common species, inhabiting both 
slopes of Panama and Colombia, is discussed under A. fasciatus and 
A. kompi. It is most readily recognized by its large black caudal spot, 
which does not extend to the end of the caudal rays; and by the 
moderate number, namely 7, of longitudinal rows of scales between 
the lateral line and the base of the first dorsal ray, and 5, or more 
commonly 6, rows between the lateral line and the base of the ventral. 
It rarely exceeds a length of 100 mm. (4 inches), the usual length 
being around 75 mm. (3 inches). 

Specimens were collected at the La Jagua Hunting Club, and in 
various Pacific slope streams along the Chepo Highway near Panama 
City; also, at Campana in the Rio Capira, in several streams crossing 
the National Highway between Campana and La Venta, and in a 
small stream along the road to El Valle, but not in El Valle. Many 
specimens were seined in the Rio Cocoli and Miraflores Lake. 
Others from the Pacific drainage are from Fort Kobbe, and Albrook 
Flying Field. In the Atlantic drainage this species was taken in the 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 259 

Rio Boqueron, above Madden Lake, and in Madden Lake; in some 
small creeks crossing Madden Dam Road; in Chillibrillo Cave (where 
this species and a catfish, Rhamdia wagneri, only were found); in 
Gatun Lake at Gatun, Gamboa, a short distance below Madden Dam, 
at Saddle Ridge, and Barro Colorado Island, and various places 
in the open lake; in abandoned reservoirs at Gatun and Mount Hope; 
and in running streams at Fort Sherman (Toro Point), and Cativa. 

This species is common and may be seen and taken almost any- 
where in streams, swamps, and lakes of central and eastern Panama. 
It is the most numerous of all fresh-water fishes of the Canal Zone, 
having become exceedingly abundant in Gatun and Miraflores lakes. 
A small piece of bread, banana, meat, or other food, thrown into the 
water, brings dozens of these little fish to the surface almost immedi- 
ately. It is chiefly this species that nibbles at the bather if he remains 
quiet in the water for a few seconds. 

The large notched teeth and short intestine suggest an animal 
diet. However, in addition to insects, crustaceans, and occasionally 
a small mollusk, much debris is generally present, some of which 
can often be identified as of vegetable origin. Other parts of the 
debris sometimes consist of small flakes of meat, no doubt from 
animals too large to swallow whole. The large rasping teeth are well 
suited to cutting bites of meat from other animals. For their size 
these little characins probably are no less ferocious than the distantly 
related piranhas (the man-eating fishes) of the Amazon and Orinoco 
rivers, and it is believed that they are responsible chiefly for the 
failure of the several introductions of food and game fishes in Gatun 
Lake by the United States Bureau of Fisheries. 

As this species was common in both the Rio Chagres and Rio 
Grande basins before the opening of the Canal it is impossible to 
determine from the collections whether it uses the Pedro Miguel 
Locks as a passageway. However, as some of the other characins, 
and especially A. fasciatus, almost certainly at times do pass through 
the Pedro Miguel Locks, it seems probable that this common species 
likewise passes through them, though none was seen in the locks 
when dewatered during the writer's presence, February 20, 1937. 

Charles M. Breder of the New York Aquarium, who has collected 
extensively in Panama, some years ago called my attention in corre- 
spondence to the fact, which I also had noticed, that nearly all adult 
ruberrimus from the Pacific slope have reddish fins, whereas those 
from the Atlantic have yellowish fins. In 1935 and 1937 I gave 
special attention to this difference in color. I failed to find adults 



260 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

in the Pacific slope without pink or red fins, but I did find some 
specimens on the Atlantic side that had them. For example, I 
caught several specimens in Gatun Lake at Gatun with reddish fins. 
It might be supposed that these fish had come through the Canal 
from the Pacific side. However, I also secured several specimens 
with reddish fins in an abandoned reservoir at Mount Hope and in 
a running stream at Cativa, localities entirely separate from the 
Canal. This rather usual difference in color, then, seems to be of no 
specific significance. 

Breder (1927, p. 120) recorded many specimens from various 
localities in the Chucunaque Basin. He examined a large number 
of stomachs for food content and found about the same foods as those 
reported above for specimens from central Panama. 

This very common fish of central and eastern Panama, according 
to Eigenmann (1922, p. 144) ranges into Colombia only on the 
Pacific slope. Dr. Behre (1928) did not report it from western 
Panama, and my record (1928, p. 83) based on specimens from the 
lagunas Verde, Grande, and Gulnar, Chiriqui, proves to be an 
error, as further study has shown that the fish belong to a distinct 
species, herein named A. kompi. 

Astyanax kompi sp. nov. 

Astyanax ruberrimus Hildebrand (not Eigenmann), Copeia, No. 168, p. 83, 

1928. 

Type from Laguna Gulnar or Grande, Volcan, Pacific slope, Pan- 
ama. No. 106510 United States National Museum. Length 70 mm. 
Also 46 paratypes, length 18 to 80 mm. 

Description of the type. Head 3.8, depth 3.2, D. 10, A. 27, scales 
35. Body compressed, moderately elongate; head short; snout blunt, 
notably shorter than the large eye, 4.4 in head; eye 3.1; interorbital 3; 
mouth small, jaws subequal; maxillary a little beyond anterior margin 
of pupil, forming an obtuse angle with the premaxillary, slightly 
longer than snout and a little shorter than eye; premaxillary teeth in 
2 regular series, each with 8 teeth, those of the second series larger, 
all premaxillary teeth with 3 to 5 cusps; maxillary anteriorly with 
2 small teeth; lower jaw with 8 strong teeth having 3 to 5 cusps, 
followed on each side by abruptly smaller teeth; gill rakers short, 12 
on lower limb of first arch ; lateral line complete, moderately decurved ; 
scales rather large, 10 between dorsal and adipose, 6 complete rows 
of scales between the lateral line and base of anterior rays of dorsal, 
and an equal number between the lateral line and base of ventral; 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 261 

origin of dorsal not quite an eye's diameter nearer tip of snout than 
base of caudal; adipose over end of base of anal, rather more than 
half as far from base of caudal as from end of base of dorsal ; caudal 
fin moderately forked, the lower lobe only slightly longer than the 
upper one, about as long as head; anal rather long, its base about 
equal to length of head, 3.8 in standard length, its origin just posterior 
to base of last ray of dorsal; ventral fins scarcely to origin of anal, 
inserted a little less than half an eye's diameter in advance of dorsal ; 
pectoral failing to reach ventral by one row of scales, 1.2 in head. 
Color mostly silvery; with a fairly distinct dusky lateral band, 
nowhere as wide as eye, ending in a prominent, elongate black caudal 
spot, with a slight indication of the black extending to end of middle 




FIG. 3. Astyanax kompi sp. nov. Type, 70 mm. long. (From drawing by 
Andrew Pizzini.) 

caudal rays; humeral spot prominent, with a downward projection, 
extending on second row of scales below lateral line; a second less 
distinct spot somewhat less than an eye's diameter behind the first; 
opercle dusky; fins mostly translucent, without definite markings. 

The variations noticed in the paratypes are as follows: Head 3.5 
to 3.9, depth 3 to 3.7, D. 10 or 11, A. 27 to 30, scales 6-33 to 36-6, 
vertebrae 14 + 17 or 18 (four specimens dissected); snout 4 to 4.8 in 
head; eye 3 to 3.3, interorbital 2.8 to 3.3, pectoral 1.2 to 1.4. 

No variation in the number of teeth has been found. The exact 
shape of the 2 maxillary teeth cannot be seen without removing the 
maxillary for examination under the microscope. It then becomes 
evident that the first tooth has a long base with 6 or 7 cusps, and the 
second one, which is smaller, has 3 or 4 cusps. 



262 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

The origin of the dorsal, though nearly an eye's diameter nearer 
tip of snout than base of caudal in the type, is more usually about 
equidistant from these points in the paratypes. The base of the anal 
is equal to or a little longer than the head, 3.7 to 4.7 in standard 
length. In the young the ventrals reach the origin of the anal, and 
the pectorals to or a little beyond the base of ventrals. These fins 
do not reach quite as far in adults. 

If the scales are counted in exactly the same place each time there 
is remarkably little variation. In fact, there are constantly 6 longi- 
tudinal series between the lateral line and the base of the anterior 
dorsal ray, and a like number between the lateral line and base of 
ventral, in 21 specimens examined. 

The color is remarkably uniform in specimens of equal size. 
However, in the young the lateral band is proportionately narrower, 
and in the very young the second humeral spot is missing. The 
caudal spot does not occupy the entire width of the caudal peduncle, 
as in young A. ruberrimus. In life the fish were greenish above, 
sides and below bright silvery, and the fins mostly pinkish. 

The fish were taken in part in Laguna Gulnar and in part in 
Laguna Grande (renamed Davis in honor of a former United States 
minister to Panama), the catches not being kept separate. This 
species is the only characin that was secured. It was abundant in 
both lakes at the time of my visit (February 7, 1935). 

The lakes are at an elevation of about 4,500 feet, and supposedly 
occupy craters of extinct volcanoes. The temperature of the water 
at the surface, near shore, was 75 F. in each lake in mid-afternoon 
on February 7, 1935. 

The characin taken is close to A. ruberrimus, and specimens 
collected in these lakes by Fred J. Foster in 1924 were so recorded by 
me (1928, p. 83). However, a further study, based on a larger number 
of specimens, shows the Volcan specimens to differ sufficiently to be 
entitled to recognition as representatives of a distinct species which 
is apparently new. The specimens from Volcan are more slender, 
have larger eyes, and fewer rows of scales above the lateral line. 

The range of the depth in the standard length in 34 Volcan speci- 
mens measured is 3 to 3.7, the average for these specimens being 
3.28, whereas in 67 specimens of ruberrimus from various localities 
of both slopes of central Panama the range is 2.25 to 3.1, with an 
average of 2.66. The measurements, therefore, overlap slightly. 
However, only four specimens of ruberrimus are slender enough to 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 263 

come within the range of the Volcan material. Usually the two 
species, then, may be separated at once by the difference in the 
depth of the body. 

The number of longitudinal rows of scales above the lateral line is 
remarkably constant in both species. In 23 specimens from Volcan 
counted there are constantly 6 complete scales between the lateral 
line and the base of the first ray of the dorsal, whereas in 30 specimens 
of ruberrimus from various localities of central Panama there are 
constantly 7. It is imperative that the scales be counted in exactly 
the same place in each species in order to show the difference of the 
single row mentioned. 

The larger eye in the Volcan material is evident at once if speci- 
mens of equal size are compared, but cannot be well demonstrated by 
measurements of specimens of various sizes. In specimens ranging 
from about 50 to 80 mm. in length the eye is contained in the head 
about 2.8 to 3.1 times in the Volcan specimens, and 3.2 to 3.9 times 
in Canal Zone material. 

The writer takes pleasure in naming this 'species for the dis- 
tinguished medical entomologist of the United States Public Health 
Service, W. H. W. Komp, who accompanied the author in his investi- 
gations in the Volcan region. 

Astyanax nicaraguensis Eigenmann and Ogle. 

Astyanax rutilus nicaraguensis Eigenmann and Ogle, Proc. U. S. Nat. Mus., 
33, p. 23, 1907 Nicaragua. 

This rather doubtfully distinct species is included because of a 
record by Behre (1928, p. 319), who listed it from some small streams 
on the Atlantic slope of extreme western Panama in the Province of 
Bocas del Toro. 

This imperfectly understood species seems to differ from albeolus 
chiefly in the position of the dorsal fin, which has its origin about 
equidistant from the tip of the snout and the base of the caudal. 
It has 2 to 8 teeth on the maxillary, 27 to 32 anal rays, and 32 to 40 
scales in the lateral series. The caudal band (not spot), as in albeolus, 
extends to the end of the middle rays of the caudal. 

The range, as reported, extends from Nicaragua to extreme 
western Panama. The genus Astyanax of Central America seems to 
require much more study to determine the relationships and dis- 
tribution of the species. 

Astyanax albeolus Eigenmann. 

Astyanax albeolus Eigenmann, Bull. Mus. Comp. Zool., 52, p. 97, 1908 Rio 
Machuca, Costa Rica. 



264 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

This species is included in the Panama fauna on the basis of a 
record by Behre (1928, p. 319) who listed it from the Rio Chiriqui 
del Tire, near Caldera (Pacific slope), Chiriqui, Panama, with the 
remark: "These fishes seem to differ from Eigenmann's A. albeolus 
only in that the body is slightly less compressed and more shallow, 
and that the anal fin count is occasionally below the type." 

It apparently differs from kompi, the nearest relative among 
Panama fishes, in the deeper body; smaller scales; the more anterior 
insertion of the dorsal, which begins more than an eye's diameter 
nearer to the tip of snout than to base of caudal; and in color, the 
black lateral band (not a black caudal spot) extending prominently 
to the end of the middle rays of the fin, wherein it also differs from 
other Astyanax from Panama, exclusive of nicaraguensis. 

The following counts and proportions are from Eigenmann (1921, 
p. 290): Head 4.5; depth 2.66; D. 11; A. 26 to 30; scales 7-38-7; eye 
equal to snout, 3.5 in head. 

The species, prior to Dr. Behre's record, was listed only from 
Costa Rica. 

Bryconamericus Eigenmann. SARDINAS DE MONTANA. 

This genus is close to Astyanax, from which it differs in having a 
broader second suborbital, which is in contact with the lower limb 
of the preopercle, and does not leave a small naked triangular area 
at its suture with the first suborbital. The teeth in the premaxillaries 
are in 2 series as in Astyanax, but the first series has 10 instead of 
8 teeth (Panama species) and they are in an uneven row (at least 
in Panama species). On the maxillary, at its juncture with the 
premaxillary, there are 2 or 3 very small teeth with roundish base, 
whereas Astyanax from Panama have 2 small teeth in the same 
position, but each with a long base, the first one especially being very 
elongate. In Panama specimens of Bryconamericus, at least in 
emperador and zeteki, the vertebrae are a little more numerous, the 
formula being 15+20 or 21, whereas that for Astyanax is 14+17 or 18. 

Bryconamericus emperador (Eigenmann and Ogle). 

Astyanax emperador Eigenmann and Ogle, Proc. U. S. Nat. Mus., 33, p. 26, 

1907 Empire, Canal Zone. 
Bryconamericus emperador Meek and Hildebrand, Field Mus. Nat. Hist., 

Zool. Ser., 10, p. 283, 1916. 

Specimens were secured in 1935 and 1937 in the upper part of 
Gatun Lake (near Madden Dam), at Barro Colorado Island, and 
in a small stream on Madden Dam Road, tributary to Gatun Lake. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 265 

None were taken in Miraflores Lake, nor in the other waters sampled 
on the Pacific slope during the recent investigations. Meek and 
Hildebrand (1916, p. 284) remarked concerning the distribution: 
"It occurs on both slopes of Panama, and is always found in company 
with Astyanax ruberrimus, but much less abundant, except in the 
Rio Tuyra Basin where it outnumbers the latter." Breder (1927, 
p. 123), however, found A. ruberrimus more numerous than B. em- 
perador in the Rio Chucunaque, a tributary of the Rio Tuyra in 
which we could not collect in 1912, when several other tributaries 
were sampled. Breder (1933) did not name this species in his list 
of fishes from Barro Colorado Island, and Dr. Behre (1928) did not 
obtain it in western Panama. 

As this species occurs naturally on both slopes of central Panama, 
and as it was not taken in Miraflores Lake during the recent investi- 
gations no information was secured relative to its use of the locks 
as a passageway. 

It occurs on both slopes of central Panama and in the Tuyra 
Basin. Costa Rica records probably are referable to B. terrabensis 
Meek (1914, p. 108). 

Bryconamericus zeteki sp. nov. 

Type from a creek in El Valle, Pacific slope, Panama. No. 
106511 United States National Museum. Length 88 mm. Also 
59 paratypes, length 20 to 88 mm. 

Description of the type. Head 4, depth 3.1, D. 11, A. 26, scales 36. 

Body compressed, moderately deep; head short; snout shorter 
than eye, 3.9 in head; eye 3.2; interorbital 3.2; mouth small; lower 
jaw a little shorter than upper one; lower lip quite broad and thick, 
exceeding half the width of pupil; maxillary a little beyond anterior 
margin of pupil, forming an obtuse angle with premaxillary, notably 
longer than snout and nearly as long as eye; premaxillary with 2 
series of teeth, the outer series with 10 teeth in an irregular row, 
alternating teeth being set farther forward, the inner series with 
8 teeth set in an even row and notably larger than those of the outer 
series, all premaxillary teeth notched, having from 3 to 5 cusps; 
maxillary with 3 very small teeth anteriorly, having very low blunt 
cusps; lower jaw with 8 large teeth, having 3 to 5 cusps, followed 
on each side by abruptly smaller teeth; gill rakers small, about half 
length of pupil, 11 on lower limb of first arch; lateral line complete, 
moderately decurved, not wavy; scales moderately large, in regular 
series, 6 complete rows between lateral line and base of anterior 



266 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

rays of dorsal, and 5 between lateral line and base of ventral, 11 rows 
crossing back between dorsal and adipose, normal scales extending 
somewhat on base of caudal; dorsal fin rather high, with nearly 
straight margin, its origin equidistant from tip of snout and base 
of caudal; adipose very small, its base occupying only 1 row of scales, 
over beginning of posterior fourth of anal; caudal fin rather broadly 
forked, the lower lobe slightly longer than the upper one, scarcely 
as long as head; anal fin moderately long, with concave margin, 
its origin slightly posterior to base of last ray of dorsal, its base a 
little longer than head, 3.6 in standard length; ventrals small, extend- 
ing slightly past vent, but failing to reach origin of anal, inserted 
rather less than an eye's diameter in advance of dorsal; pectorals 
failing to reach ventrals by 1 row of scales, 1.25 in head. 

Color of preserved specimen brownish above, median line of back 
darker; lower parts pale silvery; humeral spot faint; a rather promi- 
nent lateral band, extending forward to upper anterior angle of gill 
opening, widest and most prominent posteriorly, ending in a caudal 
spot, which extends on base of caudal fin, and indefinitely to end of 
middle rays; body everywhere, except underneath, with dusky 
punctulations. Fins unmarked, except for dusky punctulations on 
the vertical ones, and on the outer rays of the pectorals. All enlarged 
teeth in both jaws with dark tips. 

The variations noticed in the paratypes are as follows: Head 3.6 
to 4, depth 2.9 to 3.1, D. 10 or 11, A. 25 to 27, scales 6 (rarely 7) 
35 to 38-5, vertebrae 15+20 or 21 (6 specimens dissected), snout 
4 to 4.5 in head, eye 2.75 to 3.3, interorbital 2.9 to 3.4, caudal 
peduncle 2.1 to 2.5, pectoral 1.15 to 1.25. 

No variation in the number and arrangement of the enlarged 
teeth in the premaxillaries and mandible has been noticed. However, 
the teeth on the maxillary vary from 2 to 3, and have a roundish 
base, instead of an elongate one as in specimens of Astyanax described 
elsewhere. The second suborbital is uniformly wide and nearly or 
quite in contact with the lower limb of the preopercle, not leaving 
a naked triangular area between the suture of the first and second 
suborbitals as in Astyanax; from two-thirds to nearly as wide as eye 
at its broadest place. The pectorals in small specimens (under about 
50 mm. in length) reach a little farther back (to base of ventrals) 
than in larger ones, as usual in young fish. In the young the lateral 
band is narrower and more clearly defined, and the caudal spot 
extends definitely to the end of the caudal rays. All the enlarged 



1938 



FRESH-WATER FISHES OF PANAMA HILDEBRAND 



267 



teeth in the jaws have brownish tips, becoming darker to almost 
black in large examples. 

The specimens from El Valle, here described, are close to B. em- 
perador of central and eastern Panama, but they differ in having the 
scales in more regular series and in fewer longitudinal rows, in having 
thicker and broader lips, a slightly smaller eye, and rather shorter 
pectorals; and they also differ slightly in color. 

In 22 specimens from El Valle only two individuals have 7 
complete rows of scales between the lateral line and the base of the 
anterior rays of the dorsal, all the rest having 6. Between the lateral 
line and the base of the ventral 5 complete rows are constantly 
present in the 22 specimens examined. In 15 specimens of B. em- 




FIG. 4. Bryconamericm zeteki sp. nov. Type, 88 mm. long. (From drawing 
by Andrew Pizzini.) 

perador from the Canal Zone, in which the rows are more difficult 
to enumerate because of their unevenness, 7 rows were counted 
between the lateral line and the base of the anterior rays of the dorsal 
in nine specimens, and 8 rows in the other six. Six rows were counted 
in all these fish between the lateral line and the base of the ventral. 
No difference in the number of scales in the lateral series seems 
to exist. 

The lower lip in the El Valle specimens is obviously thicker and 
broader, being fully half as wide as pupil, whereas in Canal Zone 
specimens (B. emperador) it is thinner and narrower, being scarcely 
half as wide as pupil. This difference might conceivably be due to 
a difference in preservation. However, the writer preserved all the 
specimens studied by the same method, the only difference being 



268 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

that the Ganal Zone specimens have been in alcohol longer, having 
been collected two years earlier. 

That the eye is slightly smaller in the El Valle specimens is evident 
only if specimens of equal size are compared. In a series of measure- 
ments, based on various sizes, the porportions overlap. However, 
in specimens ranging in length from about 70 to 90 mm. the eye is 
contained in the head about 3.1 to 3.3 times in the El Valle material 
and 2.7 to 3 times in the Canal Zone specimens. 

The pectoral fins fail to reach the base of the ventrals, except in 
the young, in the El Valle material as already shown, whereas in the 
Canal Zone specimens the pectorals reach to or beyond the base of 
the ventrals in all except very large specimens of 100 mm. and up- 
ward in length. 

In color the El Valle specimens differ in having the caudal spot 
extending more or less definitely to the end of the middle rays of 
caudal, whereas in Canal Zone specimens it projects only slightly 
on the base of the caudal rays. The tips of the teeth are not brown 
or black in B. emperador as in the El Valle specimens. 

Northward three species of this genus, scleroparius, terrabensis 
and ricae, all from Costa Rica, are known. The first is known also 
from Nicaragua and the last extends slightly into western Panama. 
The El Valle specimens seem to differ in having a rather more 
slender body, rather shorter anal, more posteriorly placed dorsal, 
and more elongate caudal spot, which extends to the end of the 
middle caudal rays. 

I have designated the El Valle specimens a distinct species, 
though their close relationship with B. emperador makes it question- 
able whether they should be considered distinct, or only a subspecies 
of emperador. 

I take pleasure in naming this fish for Professor James Zetek, 
the well-known naturalist of the Canal Zone and Panama. 

Bryconamericus cascajalensis Meek and Hildebrand. 

Bryconamericus cascajalensis Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 284, pi. 19, 1916 Rio Cascajal, Porto Bello, Panama. 

Known only from the type material from Porto Bello. 
Bryconamericus ricae Eigenmann. 

Bryconamericus peruanus ricae Eigenmann, Bull. Mus. Comp. Zool., 52, 
p. 106, 1908 Rio Chitaria, tributary of Rio Reventazon, Atlantic slope, 
Costa Rica. 

This form is included in the fauna of Panama on the basis of a 
record by Behre (1928, p. 320), who listed it from the Atlantic slope 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 269 

of extreme western Panama, province of Bocas del Toro, under the 
name B. peruanus ricae. However, Eigenmann (1927, p. 393) raised 
ricae to full specific rank. It differs from the other Panama species 
herein recognized in the more anterior position of the dorsal fin, 
the origin of which is described as being an eye's diameter nearer 
to snout than base of caudal. It seems probable from published 
accounts that ricae may have somewhat more numerous scales and 
anal fin rays than the other Panama forms, the numbers given being, 
scales 7-39 to 40-6, anal 28 to 31. A comparison of specimens, which 
has not been possible, probably would reveal other differences. 

Known from the Atlantic slope of Costa Rica, and somewhat 
across the border in Panama. 

Hemibrycon dariensis Meek and Hildebrand. 

Hemibrycon dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 285, pi. 20, 1916. 

Originally described from specimens taken in several different 
places in the Rio Tuyra and its upper tributaries. Breder (1927, 
p. 123) recorded dariensis from several localities on the Rio Chu- 
cunaque and its tributaries. To date it is known only from the 
Tuyra Basin. 

Hyphessobrycon Durbin. 

A single species of this genus is known from Panama. The genus 
is characterized by the short compressed body with elevated back, 
by the presence of two series of premaxillary teeth, by the incomplete 
lateral line, and by the naked and unmodified caudal fin in both sexes. 

Hyphessobrycon panamensis Durbin. 

Hyphessobrycon panamensis Durbin, in Eigenmann, Bull. Mus. Comp. Zool., 
52, p. 101, 1908 Rio Boqueron, Panama; Meek and Hildebrand, Field 
Mus. Nat. Hist., Zool. Ser., 10, p. 287, 1916. 

Taken only in the Chagres Basin in 1911 and 1912. In 1935 I 
secured specimens in Gatun Lake near Gatun, and in a small stream 
flowing into Gatun Lake crossing Madden Dam Road. Behre (1928, 
p. 318) reported it from some small streams of the Atlantic drainage 
of extreme western Panama, where it seems to be common. 

It is a small species, apparently rarely exceeding a length of 50 
mm. It is most readily distinguished from the other small characins 
of the vicinity by the incomplete lateral line, which is present on 
only about 8 to 13 scales, and by the rather plain color. This species 
has no caudal spot, though it does have a narrow dark lateral band, 
at least on the posterior half of the body. It also has a vertically 



270 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

elongate dusky shoulder spot, usually followed by a second less 
distinct spot. Furthermore, it has an ill-defined dark band on the 
median line of the back. The fins are unmarked, except for dusky 
punctulations. 

The following counts and measurements are based on 6 speci- 
mens (unless otherwise stated), ranging in length from 30 to 47 mm.: 

Head 3.5 to 3.6, depth 2.5 to 2.8, D. 10 or 11, A. 24 or 25, P. 11 
or 12, scales 6 or 7-30 to 33-5 or 6, vertebrae 13+18 (one specimen 
counted). Distance from snout to dorsal 1.6 to 1.8 in standard 
length, base of anal 3.2 to 3.4, pectoral 4 to 4.5. Snout 4.5 to 5.5 in 
head, eye 2.5 to 2.8, interorbital 3.4 to 3.9. Premaxillaries with 2 
series of teeth; the outer series with 3 teeth on each side; inner series 
with 4 larger teeth on each side; maxillary with 2 or 3 very small 
teeth anteriorly; mandible with 1 series of teeth, with 4 enlarged 
ones anteriorly on each side, followed by smaller ones; all teeth with 
3 to 5 cusps. 

The range apparently extends along the Atlantic slope from the 
Panama-Costa Rica border to the Magdalena Basin in Colombia. 

Thoracocharax Fowler. 

The species of this genus are characterized by the short, deep, 
compressed body with a greatly dilated thoracic region, which, 
together with the abdomen, forms a semicircular disk with a sharply 
compressed edge. An adipose fin is present, the pectoral fins are 
large, and the anal long (with 33 to 36 rays in Panama species). 

The genus is widely distributed, ranging from Panama southward 
to Paraguay. The species are rather extensively used as "pet fish" 
in home aquaria. The peculiarly expanded thoracic region with 
sharp edge has suggested the name "hatchet fish," which is used by 
aquarists. The large pectorals and the ability to "skip" some dis- 
tance over the water has called forth the name "fresh- water flying 
fish," which also is used by aquarists. Because of the "flying" pro- 
pensities it is necessary to cover (screen) the aquaria in which these 
fishes are kept. 

Thoracocharax maculatus (Steindachner). 

Gasteropelecus maculatus Steindachner, Denkschr, Akad. Wiss. Wien, 41, 

p. 168, 1879 Rio Mamoni, Chepo, Panama. 
Thoracocharax maculatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 288, 1916. 

Taken during the recent investigation, only in swamps at the 
La Jagua Hunting Club, about 15 miles east of Panama City, where 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 271 

it was numerous. In 1911 and 1912 we took it in the Chorrera, 
Bayano and Tuyra basins, but not on the Canal Zone. All the 
specimens were collected by us either in sluggish or standing water, 
and mostly in stagnant swamps. However, Breder (1928, p. 125) 
stated, concerning his collections in the Chucunaque Basin: "Taken 
commonly only above the head of tide, in some places abundant, 
especially in fast small side streams." 

A collector of "petfish" informed me that this fish could be caught 
only at night. However, the numerous specimens taken at various 
places in Panama by us were all seined by day. It is true, neverthe- 
less, that many fish escaped either by skipping and swimming away 
from the net, or by "flying" over the cork line. Mr. Breder (1928, 
p. 125) reported some observations concerning "flight." He said 
that at night, when the fish appear to be most active, they some- 
times were seen "to leap in a shoal and travel five feet or more before 
cutting into the water again. At such times they often rise to a 
height of six inches or more from the water's surface." Mr. Breder 
has suggested that it seems probable that the large thoracic muscles 
may make it possible for the fish to use the enlarged pectoral fins to a 
limited extent as wings. 

Among the many collected at the La Jagua Hunting Club, one 
specimen, 53 mm. long, which is otherwise normal, is entirely without 
an adipose fin, the usual place of insertion being scaled over with 
normal scales. 

This species has been taken on the Pacific slope only in Panama, 
from the Rio Chorrera eastward, but not in the Canal Zone. It 
ranges into Colombia where it is known from the Rio San Juan on 
the Pacific side, and the Rio Atrato on the Atlantic. 

Creagrutus notropoides Meek and Hildebrand. 

Creagrutus notropoides Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 68, 1912 Rio Indio, upper tributary of Rio Chagres; p. 289, 
pi. 21, 1916. 

Known only from the upper Chagres Basin. 
Creagrutus affinis Steindachner. 

Creagrutus affinis Steindachner, Denkschr. Akad. Wiss. Wien, 42, p. 27, 1880 

Cauca, near Caceres. 
Creagrutus simus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 85, 1913 Rio Cupe, tributary of Rio Tuyra; p. 290, 1916. 

This species appears under the name C. simus in our earlier 
general work, as shown above. However, that name was placed 
in synonymy by Eigenmann (1922, p. 146), though there seemed to 



272 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

be a small difference in the number of longitudinal rows of scales 
between Rio Tuyra specimens (simus} and Atrato ones (affinis). 
Mr. Breder (1927, p. 124) recorded 145 specimens, ranging in 
length from 18 to 58 mm., from several places in the Chucunaque 
Basin. This fish has been found also in the Tuyra, Atrato, San Juan, 
and Cauca basins. 

Roeboides Gunther. 

The local species of this genus are readily recognized by the 
strongly compressed elongate body, which is often almost trans- 
parent. In adults the outline is deeply concave over the head. 
External tooth-like processes project forward from the upper jaw. 
The anal fin is very long (with 42 to 50 rays in Panama species), 
the adipose fin is well developed, and a large spine is situated on the 
shoulder girdle in front of the base of the pectoral. The local species 
reach a length of 150 to 170 mm. 

As the two local species of this genus of the opposite slopes of the 
Canal Zone are well differentiated in color, these fishes apparently 
would be favorable ones to show cross-breeding if it had taken place 
in the Canal. However, as stated subsequently, no evidence was 
found indicating that intermingling or crossing over has taken place. 

Roeboides guatemalensis (Gunther). 

Anacyrtus (Roeboides) guatemalensis Gunther, Cat. Fish. Brit. Mus., 5, p. 347, 

1864 Rio Chagres, etc. 
Roeboides guatemalensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 291, 1916. 

Numerous specimens were taken in Gatun Lake. The species 
was secured in 1935 and 1937, also, in an abandoned reservoir at 
Mount Hope, and in a creek tributary to Gatun Lake on Madden 
Dam Road. It is very common on the Atlantic slope of Panama, as 
stated by us (1916, p. 292), and its range extends northward into 
southern Mexico. Behre (1928, p. 318) recorded it from the Rio 
Chiriqui del Tire near Caldera, Pacific slope, with the remark: "These 
fishes (24 specimens) have hitherto been described from the Carib- 
bean coast. We found them only on the Pacific slope." 

The specific differences between this species and its relative, 
occidentalis, are shown in a key by Meek and Hildebrand (1916, 
p. 291) . The most readily available recognition mark is the difference 
in color. R. occidentalis has a large black spot on the side about an 
eye's diameter behind a rather obscure shoulder spot present in both 
species. The second black spot is missing in guatemalensis. How- 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 273 

ever, this species generally has a black streak, variable in length, 
within the silvery lateral band, which occidentalis does not have. 
The many specimens at hand from Gatun Lake, taken chiefly at 
Barro Colorado Island and in the upper end of the lake toward 
Madden Dam, have been carefully compared with an equally large 
number of specimens of the genus from the Rio Cocoli and Miraflores 
Lake. Absolutely no indication of intermingling or cross-breeding 
was found, as the Gatun Lake specimens are typical guatemalensis 
and those from Miraflores Lake and the Rio Cocoli are typical 
occidentalis. Therefore, no evidence that these species have passed 
through the Pedro Miguel Locks was obtained. 

The range of this species has been given as extending from 
southern Mexico to the Rio Chagres in Panama. Behre (1928, p. 318) 
reported it from the Pacific slope of western Panama, but did not 
get it on the Atlantic side. Meek (1914, p. 109) reported it from 
both slopes of Costa Rica. However; specimens from Liberia, 
Pacific slope of Costa Rica, studied by me (1930, p. 2) were R. salva- 
doris, a species readily separable from R. guatemalensis by the color, 
as it has no black in the silvery lateral band, but has a black spot on 
the side anteriorly, like R. occidentalis, except that the spot is much 
smaller. Evidently further study, and comparisons of specimens, 
are necessary to determine the exact distribution. 

Roeboides occidentalis Meek and Hildebrand. 

Roeboides occidentalis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 293, pi. 23, 1916. 

In addition to numerous individuals taken in the Rio Cocoli and 
Miraflores Lake in 1935 and 1937, one specimen, 85 mm. long, was 
taken in the upper chamber of Miraflores Locks (west side). Num- 
erous specimens, also, were seined in swamps at the La Jagua Hunting 
Club, and a few in the Rio Pacora. 

The differences in color between this species and its common 
Atlantic congener are pointed out in the discussion under guate- 
malensis. Although minor structural differences exist, the differences 
in color constitute the most easily used field characters for distinguish- 
ing the species. In the illustration (retouched photograph) offered 
by Meek and Hildebrand (1916, pi. 23) the prominent black lateral 
spot is shown as half above and half below the lateral line. This 
position must be regarded as unusual, at least, as in the large series 
of specimens now at hand it at most extends slightly below the lateral 
line, but is more usually wholly above it. 



274 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

No indication of intermingling of this species and guatemalensis 
through Pedro Miguel Locks is evident. Indeed, neither species was 
obtained in these locks when they were dewatered in 1937, though 
one specimen of occidentalis was found in the upper chamber of Mira- 
flores Locks. No evidence was secured indicating that the species 
has passed through these lower locks to brackish and salt water, 
which it normally does not inhabit. 

Breder (1927, p. 126) reported this species as "Not common, but 
taken in all the larger streams except the Rio Chico and Tupisa" in 
the Chucunaque Basin. It is known only from the Pacific slope of 
central and eastern Panama. On the Pacific slope of Colombia, and 
probably Ecuador, according to Eigenmann (1922, p. 162), it is 
replaced by R. hildebrandi; and if Dr. Behre's identification (1928, 
p. 318) is correct it is replaced by R. guatemalensis (of the Atlantic 
slope) on the Pacific side in western Panama. 

Brycon Muller and Troschel. SABALO PIPON. 

The common name of all the species of this genus among the 
natives of Panama seems to be "sabalo pipon," meaning an obese her- 
ring. These fishes reach a moderately large size, examples upward of 
2 feet (60 cm.) in length, at least of B. chagrensis, having been seen. 
They are valued as food, though quite bony. Although their teeth 
are relatively large and numerous, suggesting an animal diet, the 
alimentary canal is rather long, as in herbivorous fishes. Stomach 
contents show that the diet is a mixed one, consisting of both animal 
and plant remains. It is noteworthy that these fishes may be caught 
either with meat bait or with banana and perhaps other vegetable 
baits. 

The collections made by Dr. Behre in western Panama in 1923, 
and the recent ones (1935 and 1937) by the writer in central Panama 
and westward to El Valle, contain three species of Brycon not in- 
cluded in our earlier work (1916), two of which apparently are new. 
A new key including the species added to the fauna of Panama is 
introduced. 

The close relationship of the new species described from the 
Pacific slope (see p. 222), west of the Canal Zone, with species occur- 
ring in the Chagres Basin suggests a recent "crossing over" from the 
Atlantic to the Pacific slope. Both striatulus and argenteus of the 
Pacific watershed of central Panama are apparently replaced on 
the Pacific slope of western Panama by near relatives of chagrensis 
and petrosus of the Chagres Basin. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 275 
KEY TO SPECIES OF BRYCON 

a. Scales small, 64 to 83 between upper angle of gill opening and base of caudal; 
anal fin much longer than head, with 30 to 37 rays. 

6. Mandibular teeth very large and strong, usually 8 (rarely 7 or 9) in outer 
series; maxillary teeth very small and few, only 9 or 10 present; pre- 
maxillary teeth small, 12 to 14 in outer series; scales moderately large, 
64 to 73, usually fewer than 70, 18 to 21 rows crossing back between 
dorsal and adipose striatulus. 

bb. Mandibular teeth rather smaller and more numerous, usually more than 10 
in outer series; premaxillary teeth larger and more numerous, 15 or 
more in outer series. 

c. Pectoral long, frequently reaching nearly or entirely to base of ventral, 
sejdom falling short of this point by more than 2 rows of scales, 4.1 to 
5 in standard length ; scales rather small and in more or less irregular 
series, 68 to 83 (usually more than 70) between upper angle of gill 
opening and base of caudal; teeth rather small, 14 to 20 in outer series 
on mandible, 10 to 13 on maxillary, and 15 to 18 in outer series on 
premaxillaries; second suborbital narrow, with rounded lower anterior 
angle chagrensis. 

cc. Pectoral shorter, generally failing to reach base of ventral by 3 to 6 scales, 
5.2 to 5.8 in standard length; scales somewhat larger and in more 
regular series, 66 to 79 between upper angle of gill opening and base 
of caudal; teeth somewhat larger, 10 to 14 (rarely 16) in outer series 
on mandible, 12 to 15 on maxillary, and 17 to 20 in outer series on 
premaxillaries; second suborbital broad, its lower anterior angle 
less rounded behreae sp. nov. 

aa. Scales larger, 43 to 58 between upper angle of gill opening and base of caudal ; 
anal fin little if any longer than head, except in guatemalensis. 

d. Anal fin notably longer than head, with 32 to 38 rays; scales moderately small, 
50 to 56 between upper angle of gill opening and base of caudal, 10 rows 
between lateral line and origin of dorsal, 4 or 5 between lateral line and 

base of ventral guatemalensis. 

dd. Anal fin about equal to length of head, with 24 to 28 rays. 

e. Scales moderately small, 48 to 58 between upper angle of gill opening and 
base of caudal, 7 to 10 rows between lateral line and origin of dorsal, 
3 or 4 between lateral line and base of ventral, and 15 to 18 series 
crossing back between dorsal and adipose. 

/. Pectoral long, reaching nearly or fully to base of ventral in small speci- 
mens, proportionately shorter in adult, about 1.2 in head; snout 
strongly projecting, 2 rows of teeth exposed in advance of lower 
jaw; teeth rather large, 8 to 10 enlarged ones in outer series on 
mandible, 12 to 14 in outer series on premaxillaries; scales rather 
small, 53 to 58 between upper angle of gill opening and base of caudal ; 
sides with more or less definite dark cross bars or reticulations formed 

by black margins on the scales petrosus. 

ff. Pectoral rather shorter, failing to reach ventral in small specimens by 
2 or 3 rows of scales, about 1.4 in head; snout projecting less 
strongly, leaving only one row of premaxillary teeth exposed in 
advance of lower jaw; teeth smaller, though apparently equal in 
number; scales somewhat larger, about 48 to 55; sides plain 

silvery obscurus sp. nov. 

ee. Scales larger, 43 to 48 between upper angle of gill opening and base of 
caudal, 7 or 8 rows between lateral line and origin of dorsal, 3 between 
lateral line and base of ventral, and 11 to 14 series crossing back 
between dorsal and adipose; snout projecting very little, with lower 
jaw reaching outer row of premaxillary teeth argentens. 



276 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Brycon striatulus (Kner). 

Chalcinopsis striatulus Kner, Sitzber. Bayer. Akad. Wiss., Munchen, p. 226, 

1863 Panama. 
Brycon striatulus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 294, 1916. 

No specimens of this species were secured during the recent 
investigations. A discussion of its relationship with chagrensis is 
included in the account of that species. 

Since the publication of our earlier work, Breder (1927, p. 119) 
recorded this fish from several localities in the Chucunaque Basin, 
and Behre (1928, p. 317) listed B. striatulus from an upper tributary 
of the Rio Chiriqui on the Pacific slope of far western Panama. 
However, the specimens so listed by Dr. Behre are apparently 
representatives of a new species herein named B. behreae. 

The species has been taken only from streams on the Pacific 
slope of central and eastern Panama, from the Rio Chorrera to the 
Rio Tuyra. 

Brycon chagrensis (Kner). 

Chalcinopsis chagrensis Kner, Sitzber. Bayer. Akad. Wiss. Munchen, p. 223, 

1863 Rio Chagres. 
Brycon chagrensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 295, 1916. 

Many specimens were taken in the upper part of Gatun Lake, 
that is, between Gamboa and Madden Dam. Additional specimens 
were taken in Miraflores Lake and the Rio Cocoli, tributary to 
Miraflores Lake, and one in Pedro Miguel Locks. 

B. chagrensis is an Atlantic slope species, heretofore definitely 
recorded only from the Rio Chagres Basin. To reach Miraflores Lake 
and the Rio Cocoli the fish had to pass through Culebra Cut and 
Pedro Miguel Locks. 

The closest Pacific slope congener, B. striatulus, which is known 
from the Tuyra, Bayano, Juan Diaz, and Chorrera rivers, was not 
taken in the Rio Grande system (the main stream having been 
destroyed during the construction of the Panama Canal) in 1911 
and 1912, before the opening of the Canal, when rather thorough 
collecting was carried out in its then largely undisturbed tributaries. 
Nor was it ever recorded from this river basin. As it does not appear 
in the recent collections, and as the specimens of chagrensis (and 
petrosus) seem quite typical, showing no signs of cross-breeding, it 
may perhaps be assumed that striatulus does not occur in the Rio 
Grande Basin. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 277 

B. chagrensis has been synonymized with B. striatulus (Kner) by 
various authors (Regan, 1908, p. 169: Behre, 1928, p. 317; Jordan, 
Evermann and Clark, 1928 [1930], p. 98). This treatment has led to 
a careful recheck of the species of Brycon from the opposite slopes 
of Panama. 

There can be no reasonable doubt about the specific distinctness 
of the specimens from the Atlantic and Pacific drainages of eastern 
Panama. The differences were mostly correctly indicated long ago 
by Kner and Steindachner (Abhandl. Bayer. Akad. Wiss. Miinchen, 
10, 1866, pp. 38 to 43, pi. 5, figs. 2 and 3), who made the mistake, how- 
ever, of stating that striatulus has 8 to 10 mandibular teeth in the 
outer series "an jederseits" and chagrensis 14. "On each side" is 
clearly a mistake, for the species do not have as many teeth as 
twice the number given, as shown by the excellent illustrations 
offered. The number given is plainly the total number of enlarged 
mandibular teeth, which are followed on each side by about 2 or 3 
smaller ones. 

The differences between B. striatulus and chagrensis were stated 
in greater detail by Meek and Hildebrand (1916, pp. 293 to 299), 
who pointed out a difference also in the size and number of maxillary 
teeth, those of striatulus being small, and only 9 or 10 in number, 
whereas those of chagrensis are larger and more numerous, each 
maxillary being provided with 12 or 13 teeth. These data have been 
rechecked with specimens and found to be correct. It may be added 
that a similar difference in size and number in the outer series of 
premaxillary teeth exists, striatulus having 12 to 14 rather small 
teeth and chagrensis 16 to 18 somewhat larger ones. 

Kner and Steindachner pointed out that striatulus has larger 
scales than chagrensis. This difference is only an average, instead 
of an absolute one, as already shown by Meek and Hildebrand. The 
overlapping is due in part to a rather large variation in the actual 
number of series of scales present, and also in part no doubt to 
errors and to differences in place of enumeration. The scales are small 
and the series not always very regular, making them difficult to count 
accurately, especially in small specimens. The writer has enumerated 
the lateral series of scales of one specimen several times and obtained 
results that differed by as much as 5 scales. Furthermore, it makes 
a difference whether the series is counted along the upper part 
of the side from the upper anterior angle of the gill opening to the 
base of the caudal, or lower down, along the lateral line between the 
margin of the opercle and the base of the caudal where the scales 



278 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

are larger. If the series is taken along the upper part of the side, 
between the upper angle of gill opening and the base of the caudal, 
the range for striatulus may stand as 64 to 73, and for chagrensis as 
70 to 83. Generally striatulus has fewer than 70 and chagrensis more 
than 70 oblique series of scales on that part of the side. 

There is so little difference in the color patterns of the two species 
that they cannot be separated on that basis, although large speci- 
mens of striatulus often lack the blackish crossbars or reticulations 
which are always retained in life by chagrensis, so far as can be 
determined from the material at hand. 

This species remains known only from the Chagres Basin. 

Brycon behreae sp. nov. 

Brycon striatulus Behre (not Kner), Ann. Carnegie Mus., 18, p. 317, 1928. 

Type from Rio Chiriqui del Tire, above Caldera, Pacific slope, 
western Panama. No. 5582 California Academy of Sciences. Total 
length 330 mm., standard length 265 mm. 

Description of the type. Read 4.75; depth about 3.2; D. 11; A. 32, 
including undivided rays; scales 68. 

Body rather robust; caudal peduncle slender, its depth 2.5 in 
head; head short, deep; snout rather short, conical, 3.2 in head; eye 
4.5; second suborbital broad, leaving little of the cheek exposed, its 
lower anterior angle nearly a right angle, its depth at vertical of 
posterior margin of pupil 5 in head; mouth moderate, maxillary 
reaching opposite middle of eye; lower jaw shorter than upper, leaving 
2 rows of teeth exposed in advance of it; teeth large, the premaxillary 
ones laterally in 2 series, anteriorly more or less definitely in 4 series, 
the outer series with a total of 17 teeth, each maxillary with 15 teeth, 
mandible with a total of 15 teeth; gill rakers slender, scarcely as long 
as pupil, 16 on lower limb of first arch; lateral line complete, decurved 
anteriorly; scales firm, with very prominent striae, in regular series 
on sides, 24 rows crossing back before dorsal, 19 between dorsal and 
adipose, 14 rows between lateral line and origin of dorsal, and 7 rows 
between lateral line and base of ventral; dorsal with straight margin, 
its origin equidistant from snout and base of caudal; caudal broadly 
forked, the lower lobe about an eye's diameter longer than the 
upper one; anal fin elevated anteriorly, the last 12 or 13 rays of about 
equal length, its origin a little posterior to vertical from end of base 
of dorsal; ventrals failing to reach vent by 5 rows of scales; pectorals 
short, failing to reach ventrals by 6 rows of scales, 5.7 in standard 
length. 




279 



280 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

-Color bluish silvery above, pale below; a black vertical band 
under and behind opercular margin, middle of sides with rather 
prominent black bars; a black blotch at base of caudal; ventrals pale; 
all the other fins more or less dusky, at least on membranes. 

This species is based on specimens collected in the Rio Chiriqui 
del Tire and tributaries, Rio Chiriqui Basin, Pacific slope of western 
Panama, in the general vicinity of Caldera, by Dr. Ellinor H. Behre, 
for whom I am pleased to name the species. This material is now 
mostly in the museum of the California Academy of Sciences and 
the Carnegie Museum. Through the kindness of H. Walton Clark 
of the first mentioned institution, and Arthur W. Henn of the latter, 
I have been able to compare 31 specimens of Dr. Behre's collection 
with many specimens from central and eastern Panama. 

The specimens from the Pacific slope of western Panama (behreae) 
were identified as Bryant striatulus by Dr. Behre, who regarded 
B. chagrensis as a synonym of striatulus. However, well-marked 
characters distinguish the two, as shown in our earlier work (1916), 
and restated with some additions in this paper in the account of 
B. chagrensis. B. striatulus is not represented among Dr. Behre's 
specimens from the Pacific slope of western Panama examined by 
me. The specimens are so closely related to chagrensis, however, 
that they seem scarcely specifically distinct. Some differences have 
been noticed, as shown subsequently. 

It is very interesting to find striatulus apparently replaced by a 
very close relative of chagrensis on the Pacific slope of western Pan- 
ama. It is of interest, furthermore, that Dr. Behre (1928, p. 318) did 
not find chagrensis in the streams of the Atlantic slope of western 
Panama, but reported instead B. guatemalensis. To date, then, 
B. chagrensis remains known only from the Chagres Basin. 

The specimens from the Pacific slope of western Panama (behreae) 
vary more prominently among themselves than Chagres River 
specimens (chagrensis). Because of the great variations some of the 
specimens differ rather strikingly from those of the Chagres, but 
others are distinguished with difficulty, and still others are inter- 
mediate. The most constant character in which the specimens from 
western Panama differ is the shorter pectoral fin, as shown by the 
proportional measurements given subsequently. The average 
number of scales in a lateral series also is a little lower; the teeth, 
though usually agreeing in number are larger; often the snout pro- 
jects less prominently, though that is a very variable character 
among specimens from western Panama, as in some specimens only a 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 281 

single row of premaxillary teeth is exposed whereas in others as many 
as three rows are in advance of the lower jaw; the body in the larger 
specimens seems to be rather more robust, but accurate measurements 
cannot be made as the specimens have been eviscerated, the smaller 
specimens are quite as slender as those from the Chagres River; and 
the second suborbital is generally broader with a sharper lower 
anterior angle, leaving less of the cheek exposed. The color of 
preserved specimens is nearly identical, the dark bars on the sides of 
large specimens being a little more prominent on the western Panama 
material. 

The following counts and proportions are based on 21 specimens 
collected in the Rio Chiriqui Basin, western Panama, and on 22 speci- 
mens from the Rio Chagres Basin. Counts and proportions of the 
latter are placed in parentheses: Head 3.5 to 4.7 (4 to 4.8); depth 
3 to 3.7 (3.2 to 3.5); D. 10 or 11 (11); A. 32 to 35 (30 to 36); scales 
66 to 79, average 71 (68 to 83, average 74.5); rows of scales crossing 
back in front of dorsal fin 20 to 27, average 24.4 (25 to 30, average 
26.4); rows of scales crossing back between dorsal and adipose 16 to 
22, average 20 (18 to 25, average 21.1). Snout 3.4 to 4.1 (3.5 to 3.8) 
in head; eye 3.2 to 3.8 (3.4 to 4.1); pectoral 1.2 to 1.35 (1 to 1.2) in 
head, or 5.2 to 5.8 (4.1 to 5) in standard length. Teeth in outer row 
on premaxillary 17 to 20 (15 to 18) ; teeth on maxillary 12 to 15 (10 to 
13) ; teeth in outer series on mandible 10 to 16, average 13 (14 to 20, 
average 16.7). 

Brycon guatemalensis Regan. 

Brycon guatemalensis Regan, Biol. Cent. Amer., Pisces, p. 168, 1907 Guate- 
mala, Atlantic drainage; Behre, Ann. Carnegie Mus., 18, p. 318, 1928. 

This species is included in the list of Panama fishes on the basis 
of a record by Behre (1928, p. 318), who recorded it from the Rio 
Guarumo and the Rio Cricamola, both emptying into the Chiriqui 
Lagoon, Atlantic slope of western Panama. 

I have not seen Dr. Behre's specimens, but have examined 8 
specimens of guatemalensis in the National Museum, from Guate- 
mala and Nicaragua. The species is readily recognized by the long 
anal fin, which is longer than the head and has 32 to 38 rays (including 
simple rays), and by a moderate number of scales, there being 50 to 
56 oblique series along middle of side between the upper angle of gill 
opening and base of caudal, 9 or 10 longitudinal rows between the 
lateral line and origin of dorsal, and 4 or 5 rows between the lateral 
line and base of ventral. This combination of anal fin ray and scale 
counts is found in no other species of the genus known from Panama. 



282 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

The teeth are rather small and numerous; premaxillaries with 16 or 
17 in the outer series, maxillary with 16 or 17, and mandible with 10 
large ones, followed on each side by 2 or 3 smaller ones, in the outer 
row. The relationship of this species to argenteus, a rather near 
relative, is discussed in the account of the last-named species. 

As here understood, this species ranges on the Atlantic slope from 
Guatemala to Western Panama. 

Brycon petrosus Meek and Hildebrand. 

Brycon petrosus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 
p. 184, 1913 upper Chagres; and p. 297, pi. 24, 1916. 

Small specimens were taken in the Rio Boqueron, in current 
at the edge of Madden Lake; in a rocky creek, tributary to Gatun 
Lake, near Madden Dam; and in the Rio Cocoli. B. petrosus was 
previously recorded only from the Chagres Basin. It no doubt 
reached the Rio Cocoli by passing from Gatun Lake through Culebra 
Cut, the Pedro Miguel Locks, and Miraflores Lake. 

A close relative is its Pacific slope congener, B. argenteus. Though 
that species is recorded from streams both east and west of the 
Panama Canal, namely, from the Tuyra, Bayano and Chorrera 
rivers, it has not been found in the Rio Grande drainage. Since 
fairly thorough collecting has been done it may be assumed that the 
species does not occur in such parts of this river system as remain, 
because the main stream was destroyed in the construction of 
the Canal. 

B. argenteus differs from petrosus chiefly in having larger scales. 
The first named has from 43 to 48 oblique series of scales on the side 
between the upper angle of the gill opening and the base of the 
caudal ; 7 or 8 longitudinal rows between the lateral line and origin of 
dorsal; 3 between the lateral line and base of ventral; and 11 to 14 
series crossing the back between the dorsal and adipose. B. petrosus, 
on the other hand, has 53 to 58 scales along the side, counted in the 
same way; 9 or 10 rows between the lateral line and origin of dorsal; 
3 or 4 between the lateral line and base of ventral; and 15 to 18 series 
between dorsal and adipose. 

Brycon argenteus and petrosus both differ from striatulus and 
chagrensis in having larger scales, the combined range being 43 to 
58 in lateral series in the first two and 64 to 80 in the last two. 
Also, the anal fin is shorter in argenteus and petrosus which have a 
combined range of 24 to 28 rays, including the simple ones, whereas 
striatulus and chagrensis have 30 to 37 rays. 



1938 



FRESH-WATER FISHES OF PANAMA HILDEBRAND 



283 



The close relationship of this species to B. obscurus sp. nov. is 
pointed out in the discussion of that species. 

Brycon obscurus sp. nov. 

Type from a creek in El Valle, Pacific slope, Panama. No. 106512 
United States National Museum. Total length 96 mm., standard 
length 77 mm. 

Head 3.7; depth 3.5; D. 10; A. 28, including undivided rays; 
scales 55. Body elongate, compressed; dorsal profile rather more 
strongly curved than the ventral; snout moderately pointed, 3.8 in 
head; eye 3.5; interorbital 3.35; lower jaw moderately long with a 
broad lip about three-fourths diameter of pupil, covering second 
series of premaxillary teeth; maxillary not quite reaching middle 




FIG. 6. Brycon obscurus sp. nov. Type, 
Andrew Pizzini.) 



mm. long. (From drawing by 



of eye, 2.3 in head; premaxillary teeth anteriorly in 3, and laterally 
in 2 series, a total of 14 small tricuspids in the outer series; about 12 
very small ones on maxillary; teeth in lower jaw large, anteriorly 8 
large ones with 3 to 5 cusps, followed on each side by 1 or 2 smaller 
teeth (teeth on right side of lower jaw abnormal, apparently having 
been broken, being without cusps); gill rakers scarcely more than 
half the diameter of pupil, 14 on lower limb of first arch; lateral line 
strongly decurved; scales moderately small, 10 rows between lateral 
line and base of dorsal, 4 between lateral line and base of ventral, 15 
rows crossing back between dorsal and adipose; dorsal with very 
slightly concave margin, the longest anterior rays reaching somewhat 
beyond the posterior ones if deflexed, its origin about midway be- 
tween base of ventrals and origin of anal, equidistant from anterior 



284 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

margin of eye and base of caudal; caudal deeply forked; anal fin 
moderately long, its base equal to head, the origin just behind base 
of dorsal ; ventral fins reaching vent; pectorals failing to reach ventrals 
by 2 or 3 rows of scales, 1.4 in head. 

Color mostly plain silvery; back bluish; a short dark vertical bar 
at shoulder; no other dark cross-markings; a dusky blotch on opercle; 
base of caudal with a prominent elongate black spot. No lateral 
band; posterior half of body with a horizontal line along middle of 
side. Fins unmarked, except for dusky chromatophores. 

In addition to the type, 5 paratypes, ranging in length from 42 to 
52 mm., are at hand. These small specimens are more slender than 
the larger one, as usual in this genus, the depth being contained 3.6 
to 3.8 times in the standard length. The scales are rather difficult to 
count. However, the range seems to be 48 to 54, with 10 or 11 com- 
plete rows between the lateral line and base of dorsal, and 4 between 
the lateral line and base of ventral. Eight enlarged teeth in the lower 
jaw are constantly present. The range in the number of anal rays 
is 25 to 28, including the simple ones. The small specimens are less 
silvery than the type, and have an obscure dusky lateral band. In 
other respects they are similar to the type in color. 

This species is close to petrosus, a species indigenous to the upland 
streams in the Rio Chagres Basin. More and larger specimens are 
required to determine the exact relationship. However, the El Valle 
specimens appear to be more slender. This difference is evident only 
if specimens about equal in size are compared, as the species of this 
genus tend to become deeper with age. The eye, also, has the 
appearance of being smaller, and the snout projects less strongly 
beyond the lower jaw, the second series of premaxillary teeth being 
well in advance of lower lip in petrosus, whereas in the present species 
the lower lip almost if not quite covers the second series. The lower 
lip in the El Valle specimens seems to be broader and thicker, being 
fully three-fourths the width of pupil, whereas in petrosus it is 
scarcely half as wide as pupil. The teeth, especially the maxillary 
and premaxillary ones, are rather smaller in the El Valle specimens, 
though the average number may be equal. The pectoral and ventral 
fins have the appearance of being rather shorter, failing by 2 or 3 
rows of scales to reach, respectively, the base of the ventrals and the 
origin of the anal, whereas in young petrosus these fins usually reach 
the points named. Finally, the species differ in color. The El Valle 
specimens are plain silvery on sides, none of the scales having dark 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 285 

margins, whereas in young petrosus many scales have dark margins, 
tending to form blackish reticulations or crossbars. 

If more and larger specimens come to hand, other and more 
distinctive characters may become evident. Though the relationship 
with petrosus of the Chagres River (Atlantic drainage) is close, it 
seems improbable that the El Valle specimens (Pacific drainage) will 
prove to be identical. It is interesting, however, that the relationship 
of petrosus is nearer to the El Valle specimens than to argenteus, 
occurring in the Chorrera and Bayano rivers, immediately opposite 
the Chagres. To date no identical specimens from the opposite 
slopes of eastern Panama have been found among many specimens 
examined by the writer. Recently (1935 and 1937) the writer took 
both B. chagrensis and B. petrosus in the Rio Cocoli, now tributary 
to Miraflores Lake, and chagrensis in Miraflores Lake. However, 
these waters are accessible to the fishes from the Chagres River (or 
Gatun Lake) by passing through Culebra Cut and Pedro Miguel 
Locks. 

The El Valle specimens differ from argenteus, a species of the 
streams of the Pacific slope of eastern Panama, principally in having 
notably smaller scales. B. argenteus has about 43 to 48 oblique series 
of scales on middle of side between the margin of the opercle and base 
of caudal, 7 or 8 complete longitudinal rows between the lateral line 
and origin of dorsal, and only 3 between the lateral line and base 
of ventral. 

Brycon argenteus Meek and Hildebrand. 

Brycon argenteus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 
p. 84, 1913 Rio Aruza, tributary of the Tuyra; ibid., p. 298, pi. 25, 1916. 

This species was not among the recent collections. It is not 
recorded from the Canal Zone, though it has been taken in Pacific 
slope streams east and west of the Canal Zone, as pointed out in the 
discussion of B. petrosus, its nearest relative. A discussion of the 
relationship of this species is introduced here because its validity 
has been questioned, which led the writer to make a further study 
of its relationship with other species of the genus. The results of 
this further study, principally of specimens, are included partly in 
the account of B. petrosus and partly in the following paragraphs. 

The question of the identity of this species with B. guatemalensis, 
a Central American species presumably only of the Atlantic slope, 
was brought up by Behre (1928, p. 318), who quotes Eigenmann: 
"It seems very probable that B. argenteus is identical with this 
species." I have not seen Dr. Behre's specimens, which are from the 



286 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Atlantic drainage of western Panama, but I have examined eight 
specimens from Guatemala and Nicaragua in the National Museum. 
According to Regan's original description (1908, p. 168) the speci- 
mens examined apparently are all guatemalensis and certainly all 
specifically distinct from argenteus. 

The Central American specimens differ at once in the longer anal, 
which is composed of 32 to 38 rays, and its base is much longer than 
the head, whereas argenteus has only 24 to 28 anal rays, and the base 
of the fin does not exceed the length of the head. Furthermore, 
guatemalensis has smaller scales, there being 50 to 56 in the lateral 
series, 9 or 10 longitudinal rows between the lateral line and origin 
of dorsal, and 4 or 5 between the lateral line and base of ventral, 
whereas argenteus has 43 to 48 scales in the lateral series, 7 to 9 rows 
between the lateral line and origin of dorsal, and 3 or 4 between 
the lateral line and base of ventral. Finally, guatemalensis seems to 
have smaller and more numerous teeth, the outer series in the pre- 
maxillary consisting of 16 teeth, and the outer series of mandibular 
teeth consisting of 10 enlarged ones followed at each side. by 2 or 3 
smaller ones. B. argenteus has 14 teeth in the outer premaxillary 
series, and 8 enlarged mandibular teeth. 

The relationship of this species with B. obscurus sp. nov. is pointed 
out in the account of that species. 

This fish is known from the Pacific slope of Panama from the 
Rio Chorrera to the Rio Tuyra, but not from the Canal Zone. 

Piabucina Cuvier and Valenciennes. 

The fishes of this genus have an elongate body, which is some- 
what compressed; the teeth in the premaxillaries are in one series, 
and those on the mandible are in two well-separated series; all or 
nearly all are tricuspid; the scales are large and firm (27 to 30 in a 
lateral series in Panama species); the lateral line is missing; the 
dorsal and anal fins are short (the former with 8 to 10 rays, and the 
latter with 10 to 12 in Panama species) ; and an adipose fin is present. 

Two closely related species have been recognized from Panama, 
namely panamensis and festae, the latter only from the Tuyra Basin. 
The species apparently differ chiefly in color. Both have a dark 
lateral band, but the one in panamensis originates above the posterior 
(distal) angle of the opercle, is situated on the middle of the side, 
and is often broken up into dark spots, whereas in festae this band 
begins at the posterior (distal) angle of the opercle, is below the 
middle of the side, is continuous (not broken up into separate spots), 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 287 

and does not end in a caudal spot as in panamensis. In festae a 
separate dark shoulder spot is present, which is connected with the 
lateral band in panamensis. 

Piabucina panamensis Gill. "DOMINI CANDELA." 

Piabudna panamensis Gill, Proc. Acad. Nat. Sci. Phila., p. 336, 1876 Rio 
Frijoles, Canal Zone; Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 300, 1916. 

The principal recognition marks of this characin have already 
been set forth in the account under the generic name. Its usual 
habitat is in streams among rocks where it is easily recognized by a 
bright yellow, generally elongate, spot in advance of the dorsal fin. 
This spot is much more distinct in the water than in a fish just 
removed from the water, and it fades completely shortly after death. 
In shape, behavior, and habitat this fish resembles the brook trout 
somewhat. It is a rapid swimmer, darting here and there quickly for 
cover. As it is quick in its movements and generally stays in 
rocky places it is difficult to net. However, it takes the hook readily, 
but a wire leader is necessary, as it is able to snap a line easily with 
its comparatively large sharp teeth. It apparently rarely exceeds 
a length of 200 mm., and therefore is too small to be of much value 
as food. 

Its resemblance to the trout apparently has given origin to the 
belief (or supposition) among some Canal Zone employees that it 
actually is a trout, presumably introduced by the French at the time 
a company of Frenchmen attempted to construct an Isthmian canal. 
The bright yellow spot in advance of the dorsal fin, as seen in the 
water, appearing more or less as a light, apparently had something to 
do with the origin of the local name "domini candela." 

During the breeding season, at least, adult males may be dis- 
tinguished from the females by a thickening of the tissues surrounding 
the anterior simple rays of the anal. Ripe or nearly ripe fish were 
taken during February. 

This fish evidently feeds on both animal and plant foods. A large 
seed, some leaves of an unidentified plant, and vegetable debris were 
found in the several stomachs examined. The same fish had fed also 
on insects, and one had ingested a small shrimp. 

This species was secured during the recent investigations in the 
Atlantic drainage at Cativa, Fort Sherman (Toro Point), and in a 
small stream on Barro Colorado Island. On the Pacific side it was 
collected in the Rio Cocoli (flowing into Miraflores Lake) and in the 



288 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Rio Capira near Campafia. As this fish seems to confine itself to 
rocky streams it probably never enters the Canal. 

Eigenmann (1922, p. 126) gave as the habitat of this species, 
"Panama on both slopes, Atrato Basin, and San Juan Basin." If this 
is the correct distribution it seems singular that the species has not 
been taken in the Tuyra Basin, where numerous specimens of P. festae 
have been collected. 

Piabucina festae Boulenger. 

Piabucina festae Boulenger, Boll. Mus. Torino, No. 346, 14, p. 1, 1899 
Laguna de la Pita, Darien, Panama; Meek and Hildebrand, Field Mus. 
Nat. Hist., Zool. Ser., 10, p. 301, 1916. 

Since 1916 this species has been reported from the Rio Chucunaque 
by Breder (1927, p. 117), who had 40 specimens ranging in length from 
54 to 130 mm. Mr. Breder stated: "There is a distinct dark spot near 
the bases of the fourth, fifth, and sixth dorsal rays, the fifth passing 
through its center, which is not mentioned in descriptions." 

This species, as now understood, is known only from the Rio 
Tuyra Basin. In our earlier work (1916, p. 301) we gave as habitat, 
"Rio Tuyra Basin and southward to Colombia," believing at that 
time that at least the Atrato specimens were identical with those from 
the Tuyra. However, Eigenmann (1922, p. 126) included the speci- 
mens from the Atrato and San Juan rivers under P. panamensis. 

Ctenolucius Gill. 

Ctenolucius Gill, Senate Doc. 9, Second Sess., thirty-sixth U. S. Congress, 7, 
pt. 1, 1861, p. 258 (name only); Proc. Acad. Nat. Sci. Phila., 13, Suppl., 
p. 8, 1861. 

The name Ctenolucius supersedes Luciocharax, used by us (1916, 
p. 302), because of the law of priority. Gill did not name a type for 
Ctenolucius, but Jordan sets forth the case in his "The Genera of 
Fishes" (pt. Ill, 1919, p. 302) as follows, "Ctenolucius Gill, 8; ortho- 
type not named = Luciocharax insculptus Steind. It is described as an 
ally of Xiphostoma, a South American Characin, identical with 
Luciocharax Steind., 1876, which name it should replace." Eigenmann 
(1922, p. 166) accepted this decision, but questioned whether Hydro- 
cynus hujeta (Xiphostoma hujeta Cuvier and Valenciennes, Hist.- Nat. 
Poiss., 22 p. 358, 1848), recorded from Maracaibo, is not identical 
with C. insculptus. 

The long, slender pike-like body, the produced, spike-like snout, 
and the firm pectinate scales readily distinguish the single species 
known from Panama from all the other local characins. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 289 
Ctenolucius beani (Fowler). 

Belonocharax beani Fowler, Proc. Acad. Nat. Sci. Phila., p. 464, 1906 Rio 
Truando, tributary of the Rio Atrato. 

Luciocharax beani Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 302, 1916. 

This species, which is the only one of the genus occurring in Pan- 
ama, differs so greatly from all other fresh-water fishes, as already 
stated in the generic account, that it is readily recognized. It is 
known only from the Pacific slope in Panama from several streams 
east of the Canal Zone, but not from the Zone itself. During the 
recent investigations it was taken only in a swamp at the La Jagua 
Hunting Club. 

A related species, C. insculplus, occurs in the Magdalena Basin, 
Atlantic slope of Colombia, differing principally in the absence of 
the dark stripes between the rows of scales along the sides. Generally 
the incomplete lateral line is present on fewer scales in that species 
than in C. beani, 17 to 28 scales having pores in the Magdalena 
fishes, whereas in the other species pores are present on 27 to 39 
scales. The Panama fish seems to prefer standing or sluggish water. 
It reaches a maximum length of about 325 mm. 

Breder (1927, p. 128) found C. beani abundant at several places 
in the Chucunaque Basin. In 78 stomachs examined he found only 
fish and decapod crustaceans, indicating that the fish are wholly 
carnivorous, as suggested by the very short intestinal canal. 

This characin is recorded from the Pacific slope of central and 
eastern Panama to the San Juan River in Colombia, and from the 
Atrato Basin of the Atlantic slope in Colombia. 

Hoplias Gill. 

The elongate, scarcely compressed body; the rather large mouth 
with strong teeth, some of them canines; the short dorsal and anal 
fins (D. 13 to 15; A. 10 or 11); and the absence of an adipose fin 
characterize this genus. 

Two closely related species are known from Panama, namely, 
microlepis and malabaricus. These usually differ in the number of 
rows of scales, the former having 11 rows across the caudal peduncle 
from the lateral line on one side to the one on the other, and 5 
complete rows between the lateral line and the base of anal, whereas 
the latter has 9 rows across the peduncle and only 4 between the 
lateral line and the base of anal. Some evidence indicating that the 
two intergrade has been found (Breder, 1927, p. 129). 



290 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Hoplias microlepsis (GUnther). PESCA PERRO; PEJEPERRO. 

Macrodon microlepis Giinther, Cat. Fish. Brit. Mus., 5, p. 282, 1864 Rio 

Chagres and western Ecuador. 
Hoplias microlepis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 303, 1916. 

This species is easily distinguished from other Panama fishes 
exclusive of the closely related one occurring in the Tuyra Basin 
and southward, mention of which was made in the account under 
the generic name. The elongate, rather robust body, which is 
scarcely compressed; the large mouth with strong teeth; the short 
dorsal with only 13 or 14 rays, placed over the mid-length of the 
back; the short anal with only 10 or 11 rays; the absence of the 
adipose fin; and the general dark brown to smutty color above, 
serve to characterize the species. It is common in lowland streams 
and swamps on both slopes of Panama, west of the Tuyra Basin. 
It is commonly found in still shallow water among vegetation, 
where it seemingly hides waiting for its prey, as it no doubt is a 
highly predatory species. It has acquired its common names, 
namely, "pesca perro" and "pejeperro," from its large teeth and the 
habit of snapping dog-like at anything coming near. If care is not 
taken it will wound the hands severely when picked up after being 
caught in a net. The species reaches a length of about 46 to 50 
cm., but it is not valued as food, being eaten sparingly. 

It is very common on both slopes of central Panama, and ac- 
cording to Eigenmann (1922, p. 169) also on the Pacific slope of 
southern Ecuador. It is not reported from western Panama. During 
the recent investigations it was not secured in the Rio Cocoli nor 
Miraflores Lake, though it doubtless occurs there. It was taken 
at Barro Colorado Island; in the upper end of Gatun Lake near 
Madden Dam, and in a small creek near the same place. This 
species seems to be less numerous in the Gatun and Miraflores 
lakes areas than it was before the opening of the Canal. It was 
very abundant in the swamps near the La Jagua Hunting Club 
in 1935, when some rather large individuals were taken and offered 
to a native, who refused them, saying they were no good. 

Hoplias malabaricus (Bloch). 

Esox malabaricus Bloch, Naturgesch. der Ausland. Fische, pt. 8, p. 149, 

pi. 392, 1794. 
Hoplias malabaricus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 305, 1916. 

This species has been recorded from 15 specimens from the 
Chucunaque Basin by Breder (1927, p. 129) since the publication 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 291 

of our earlier (1916) work. The relationship of this species and the 
preceding one is discussed in the account of the genus. 

The range is given by Eigenmann (1922, p. 170) as extending 
from the Tuyra Basin in Panama south to the Patia (southern 
Colombia) on the Pacific slope, and from the Atrato Basin in Colom- 
bia to Buenos Aires on the Atlantic slope. 

Family GYMNOTIDAE 
Gymnotus carapo Linnaeus. 

Gymnotus carapo Linnaeus, Syst. Nat., Ed. 10, 1, p. 246, 1758; Meek and 
Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 307, 1916. 

An account of this species, not then known from Panama, was 
included in our earlier work (1916, p. 307) because it was recorded 
from both north and south of Panama. Behre (1928, p. 310) reported 
two specimens from a small stream flowing into Almirante Bay, 
Atlantic slope of extreme western Panama, which is the only record 
from Panama known to me. 

The general range of this gymnotid eel extends from Guatemala 
(both slopes) to Colombia (both slopes) and southward east of the 
Andes to Rio de la Plata. 

Sternopygus dariensis Meek and Hildebrand. 

Sternopygus dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 309, pi. 26, 1916. 

This eel, first taken in the lower Tuyra (Meek and Hildebrand, 
1916, p. 309) in a very muddy tidal creek, where it was numerous, 
was later reported from El Real de Santa Maria, still lower down 
on the Tuyra, and from two localities in the lower part of the Chu- 
cunaque Basin (Breder, 1927, p. 130). It was not seen during the 
recent investigation. 

This species is known to date only from the material already 
mentioned from the lower part of the Tuyra and Chucunaque rivers. 

Hypopomus brevirostris (Steindachner). 

Rhamphichthys brevirostris Steindachner, Sitzber. Akad. Wiss. Wien, 58, p. 254, 

pi. 2, fig. 2, 1868 Guapore. 
Hypopomus brevirostris Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 310, 1916. 

This species was reported in our earlier work (1916, p. 310) 
from two specimens from the Chagres Basin and two from the 
Bayano. Since that time Breder (1927, p. 130) has reported four 
specimens from the Chucunaque Basin, and Behre (1928, p. 309) 



292 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

recorded 47 specimens from the Rio Cricamola, Atlantic slope of 
western Panama. 

It occurs in rivers on both slopes of Panama and Colombia, and 
apparently east of the Andes to Paraguay. 

Eigenmannia virescens (Valenciennes). 

Sternarchiis virescens Valenciennes, in d'Orbigny, Voy. Amer. Merid., 5, pt. 2, 

p. 11, pi. 13, fig. 2, 1847. 
Eigenmannia virescens Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 311, 1916. 

This species is not in the recent collections. We secured only 
two specimens in 1911 and 1912. These were taken at Marrigante, 
in the Tuyra, below the head of tide water. It is reported also from 
the Rio Mamoni, near Chepo, by Steindachner (1879, p. 169) under 
the name Sternopygus humboldtii, a record overlooked by us when 
preparing our earlier work. 

The range as now understood extends from the Rio Mamoni 
and the Rio Tuyra in Panama to the Rio Magdalena in Colombia 
and southward to Buenos Aires. 

Sternarchus rostratus Meek and Hildebrand. 

Stemarchus rostratus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 85, 1913 Rio Grande near Cana, Panama; p. 312, pi. 27, 1916. 

This gymnotid eel is known from Panama only from the type, 
taken in the Rio Grande, an upper tributary of the Tuyra River. 
Eigenmann (1922, p. 176) recorded several specimens from the Rio 
Magdalena on the Atlantic slope of Colombia. 

Family SYNBRANCHIDAE 
Synbranchus 1 marmoratus Bloch. 

Synbranchus marmoratus Bloch, Ichthyol., 9, p. 87, pi. 418, 1795; Meek and 
Hildebrand, Field Mus. Nat, Hist., Zool. Ser., 15, p. 131, 1923. 

Six specimens are at hand, ranging in length from 93 to 345 mm. 
Five of these, all small, 93 to 120 mm. long, are from a lily pond 
at Summit, Canal Zone, where the species was reported numerous, 
and one is from an unknown number of miles west of Balboa. The 
largest specimen was presented by G. 0. Lee, head of the department 
of biology of the junior college at Balboa, and the others were 
obtained through the interest and kindness of employees of the 
botanical station at Summit. 

1 Spelling has been corrected to Symbranchus by Eigenmann (1922, p. 177) 
and some other writers. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 293 

Breder (1927, p. 131) listed 12 specimens, eight from the Rio 
Sucubti, tributary of the Chucunaque, three from the Rio Tapia, 
near Panama City, and one from Caledonia on the Atlantic. Mr. 
Breder stated that he always found this eel buried under sand or 
rocks, which explains why it is not taken in seines. He said, also, 
that calcium carbide used as poison brought the eels out in great 
numbers in the Sucubti. These fish probably are nocturnal, as it 
is not reasonable to suppose that they always lie buried. Gilbert 
and Starks (1904, p. 34) stated that they were so abundant in a 
pond at Miraflores, Canal Zone, that they were trapped for food, 
yet none could be taken with a seine. This species was reported also 
from Barro Colorado Island, Canal Zone, by Breder (1933, p. 567). 

Breder (1927, p. 131) found the eels both above and below falls 
in the Rio Sucubti, which "held back all the other normal river 
fauna." In explanation he advanced the supposition that the eels 
probably go overland, through wet grass, around the falls. 

This species is not listed in our earlier work (1916) on the fresh- 
water fishes of Panama, as it was overlooked. However, a description 
is given in a later publication (1923, p. 131). This description was 
emended by Breder (1927). 

This eel stands in a family by itself, having no near relatives, 
so far as known. It is readily recognized by the very long body, 
which greatly exceeds the tail in length; the projecting snout; the 
rather large mouth, reaching far beyond the eye; the small confluent 
gill openings, situated on the median ventral line; and the absence 
of pectoral and ventral fins. The low, membranous dorsal begins 
a short distance in advance of the vent, and is confluent around 
the tail with the scarcely developed anal. The color is reported 
variable. The small specimens at hand are grayish, lighter below 
than above, the lighter areas underneath being finely dotted with the 
darker gray of the back. The large specimen is dark brown above, 
and the grayish under parts are definitely marked with numerous 
small brownish spots. 

The following proportions are based on measurements of the six 
specimens in the present collection. Tail in head and trunk 2.9 to 
3.1; head to gill opening in head and trunk 6 to 6.4; depth in head 
2.5 to 3; eye about 10 to 16; snout 6.4 to 6.7; gape from its posterior 
angle to tip of upper jaw 2.5 to 3.1. 

This eel is widely distributed, ranging from southern Mexico to 
the Amazon and probably southward. It has been taken on both 
slopes of central and eastern Panama. 



294 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Family ANGUILLIDAE 

Anguilla rostra ta (Le Sueur). COMMON FRESH WATER EEL; 
"ANGUILLA." 

Muraena rostrata Le Sueur, Journ. Acad. Nat. Sci. Phila., 1, p. 81, 1817 

New York. 
Anguilla rostrata Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 15, 

pt. 1, p. 134, 1923. 

This species is not listed in our earlier work (1916) because it 
was overlooked. It is recorded, however, in our work on the marine 
fishes of Panama (1923, p. 134) from one specimen from the Trinidad 
River, where it was not rare in 1911 according to native fishermen. 
Whether it is able to reach this stream since the construction of 
Gatun Dam has not been determined. If it cannot get by the 
spillway, it should have no difficulty going through the locks, 
though no specimens were taken when the locks were dewatered 
in 1935, and none in Gatun Lake nor tributary streams. Since our 
earlier investigation it has been reported, however, from nine speci- 
mens taken in small streams flowing into Almirante Bay, on the 
Atlantic slope of extreme western Panama by Behre (1928, p. 310), 
and Breder (1925, p. 140) listed young ones from the foot of Gatun 
Spillway, Canal Zone. It has been recorded also from Caldera 
Island, Porto Bello Bay by Evermann and Goldsborough (1909, 
p. 101). 

The single genus and species of this family occurring in American 
waters is recognized by the snake-like body, which is covered with 
scales that are linear, embedded, and arranged in groups placed 
more or less at right angles to each other. The lower jaw projects 
somewhat; the gill openings are separate and lateral, partly in front 
of the base of the pectoral fins; and the dorsal fin begins in advance 
of the anal a distance nearly equal to the length of the head. The 
color is uniform greenish above and pale below. 

Breeding takes place in deep water at sea. The larvae, generally 
known as leptocephali, are not eel-like, but are soft, more or less 
ribbon-shaped transparent creatures with a rather large mouth and 
large teeth. After spending a year or so in the sea, a metamorphosis 
takes place, and the young ascend fresh-water streams. 

The general range of the common fresh-water eel extends from 
southern Canada, through the West Indies, to Panama. Species of 
the genus Anguilla occur in nearly all warm seas and adjacent streams, 
exclusive of the eastern Pacific. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 295 

Family POECILIIDAE. Viviparous Top-minnows 

The members of this family are viviparous and are characterized 
by an oblong body, which is more or less depressed anteriorly, 
compressed posteriorly, and covered with rather large cycloid scales, 
The head is flat above, the mouth is protractile, the dorsal fin is 
single and consists of soft rays only, the ventral fins are abdominal, 
and the anal fin in adult males is variously modified to form an 
intromittent organ or gonopodium. 

As formerly understood this family included many oviparous 
genera, which have been assigned to a separate family, Cyprino- 
dontidae, by recent authors. Only one genus belonging to the 
oviparous group, Rivulus, occurs in Panama. This genus was 
placed in the Poeciliidae in our earlier work (1916, p. 330), but is 
now dealt with separately under the family Cyprinodontidae. 

The classification of Hubbs (1924 and 1926) has been followed 
for the most part. The use of the structure of the intromittent 
organ (gonopodium) as the principal and often the sole character for 
generic divisions in these papers has led, in my opinion, to too great 
a multiplication of genera. This classification makes it difficult at 
times to separate females of different genera, as pointed out sub- 
sequently. It is not the purpose of this paper to carry out generic 
revisions, but it is apparently proper to state (after having examined 
and used the classification referred to rather extensively) that it 
would seem more logical, and that it would simplify classification, 
if these minnows were grouped generically with reference to the 
general type of gonopodium, in combination with other characters 
that would aid in grouping the females also. 

The counts of fin rays for the members of this family include 
the simple rays, which are not shown separately. 

The members of this family have proved the most valuable 
among fishes as enemies of the mosquito. Unfortunately, those 
species in Panama that seem best suited to cope with the mosquito 
have not established themselves in abundance, as shown by col- 
lections and observations, in the artificial lakes of the Panama 
Canal. The only minnow of this family that has become very 
numerous in the lakes is Mollienisia sphenops, and it is apparently 
of limited value, as pointed out in the account of that species. 

Gambusia Poey. 

A single species of this genus occurs in Panama if the structure 
of the intromittent organ (gonopodium) is used as a basis for defining 



296 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

genera. In the present genus this organ is provided near the tip 
with two rather strong spiny hooks, directed backward and down- 
ward. This structure is shown for G. nicaraguensis in a camera 
lucida tracing by Meek and Hildebrand (1916, p. 316, fig. 4). 

The close relationship of G. nicaraguensis and Brachyrhaphis 
cascajalensis is pointed out in the following account, which shows 
that closely related species sometimes fall into different genera if 
the gonopodium is used as the sole basis for founding genera. 

Gambusia nicaraguensis Glinther. 

Gambusia nicaraguensis Giinther, Cat. Fish. Brit. Mus., 6, p. 336, 1866 
Lake Nicaragua; Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 316, 1916. 

Many specimens of this top minnow were collected on Largo 
Remo Island, at Fort Sherman (Toro Point), Mount Hope Dry 
Dock, and in Gatun Lake near Gatun and at Barro Colorado Island. 
In general, this species seems to run smaller in size than Brachyrha- 
phis cascajalensis, with which it sometimes associates and which it 
resembles greatly. The largest female taken is 45 mm., and the 
largest male 37 mm. long. In some males the intromittent organ 
is developed at a much smaller size than in others. For example, 
a fully mature male only 20 mm. long is at hand, whereas another 
equal in length to the largest male taken (37 mm.) is not yet fully 
mature, as the anal fin though considerably modified still does not 
possess the characteristic hooks of a mature male. 

This species, as already suggested, is very similar to B. casca- 
jalensis, with which it agrees in the shape of the head and body, 
the position of the dorsal fin, and the number of scales in a lateral 
series. However, nicaraguensis seems to have 1 or 2 more series of 
scales between the upper angle of the gill opening and the origin of 
the dorsal, 14 to 16 being present, whereas only 12 or 13 were counted 
in cascajalensis. Both species have a broad depressed snout, that 
has the appearance of having been squeezed to a sharp edge between 
a man's fingers. Adult males are readily distinguished by the dif- 
ferences in the structure of the intromittent organs, that of nica- 
raguensis being provided with distinct hooks distally, which are 
wanting in cascajalensis. The differences are figured by Meek and 
Hildebrand in camera lucida tracings. (1916, p. 316, fig. 4, and p. 318, 
fig. 5. Although fig. 5 is based on B. episcopi it is representative 
of cascajalensis, as the two are identical in that respect.) The 
species also differ somewhat in color. G. nicaraguensis often has 
black dots on the upper part of the sides, forming rows along the 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 297 

series of scales. Similar dots occur on the dorsal and caudal fins, 
usually forming more or less distinct crossbars. The anal fin is not 
blotched with black at the base, as in B. cascajalensis. 

The number of young born at one time seems to be rather smalt 
as in three females examined, respectively 39, 35, and 32 mm. long, 
the broods consisted of 10, 10, and 4 large embryos in addition to 
a similar number of large yellow eggs and two or three smaller sets 
of eggs. No evidence of the development of embryos in a second 
clutch of eggs before the older embryos are born was seen, as in 
some of the other local species of this family. The young are well 
developed, pigmented, and comparatively large when born, as 
embryos with nearly all the yolk absorbed are about 7 mm. long. 

The intestinal tract is very short. Three stomachs examined 
contained fragments of insects only. This is probably the most 
useful minnow in Gatun Lake as a natural enemy of the mosquito. 
It was not secured in Miraflores Lake. 

This species ranges on the Atlantic coast from Mexico to Panama 
and is doubtfully recorded from the Pacific slope of Panama. It 
inhabits lowland streams and sometimes decidedly brackish to salty 
water, though it ranges well up into fresh water as shown by its 
presence in Gatun Lake. On the other hand, the water in the Mount 
Hope Dry Dock, where it also was taken, is decidedly salty. It is an 
exceedingly hardy fish, as shown by the survival of a dozen or so 
individuals confined to a small (about a quart size) can for a period 
of three days without artificial aeration and without a change of 
water, whereupon they were placed in a small aquarium in apparently 
good condition. According to reports received, they lived there 
for months and multiplied. 

Breder (1933, p. 567) listed Gambusia affinis speciosa Girard 
from Barro Colorado Island, Canal Zone, with the remark: "This 
species is the Gambusia nicaraguensis from Panama of authors. 
Hubbs and Gordon (MS.) identify this fish with the race speciosa 
of G. affinis, native of northeastern Mexico and central Texas. 
Consequently, the present species must be an introduction from 
early Canal building days for the purpose of mosquito control." 
I have compared the recently collected specimens from Panama, 
together with others collected there, by us in 1911 and 1912, with 
specimens of Gambusia from various sections of the United States 
from New Mexico to the Atlantic coast. None of the males examined 
from the States have long prominent serrae on the third anal ray 
like the Panama material. The gonopodium in the Panama sped- 



298 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

mens before me agrees with the figures given by Hubbs (1926, pi. 2, 
figs. 1, 2, and 3) for G. nicaraguensis, as well as with the figure in our 
work (1916, p. 316, fig. 4). The Panama specimens, also, are more 
distinctly marked than the States material, the rows of scales on 
the sides, at least posteriorly, being rather definitely marked with 
rows of black dots. Similar dots are prominent on the dorsal and 
caudal fins also, where they form cross lines. It seems improbable, 
on the basis of this study, that the Panama material before me is 
the progeny of an importation. Since writing the foregoing state- 
ments concerning the introduction of minnows, I have communicated 
with Mr. J. A. Le Prince, chief sanitary inspector for the Isthmian 
Canal Commission from 1904 to 1914. Mr. Le Prince informs me 
that he knows of only one importation of top minnows, namely, 
the "millions fish" (Lebistes reticulata), which was brought from 
Barbados, and released in several places now within Gatun Lake. 
A further discussion of this importation has been given (see p. 225). 

Brachyrhaphis Regan. 

This genus is characterized by the rather short intromittent 
organ (gonopodium), which is rather less than a third of the standard 
length, and which is very simple in structure, having no hooks or 
spines, as shown by Meek and Hildebrand (1916, p. 318, fig. 5). 
The body, mouth, and dentition are very similar to Gambusia, 
under which episcopi and cascajalensis were placed in our earlier 
publication. 

The principal distinguishing characters of the three species 
collected are pointed out in the accounts that follow. 

Brachyrhaphis episcopi (Steindachner). 

Gambusia episcopi Steindachner, Sitzber. Akad. Wiss. Wien, 77, p. 387, pi. 2, 
figs. 3, 4, 1878 Obispo, Canal Zone; Meek and Hildebrand, Field Mus. 
Nat. Hist., Zool. Ser., 10, p. 317, fig. 5, 1916. 

This top minnow, although seemingly fairly common in central 
Panama during our earlier (1911 and 1912) investigations, was 
taken in only three places recently; namely, in the Rio Capira at 
Campana, in a small creek in El Valle, and in a cloudy pool remaining 
in a dry creek crossing the road shortly before entering El Valle. 
This fish alone inhabited the pool mentioned, where it was numerous. 
Some of the females were larger than any seen previously, the 
largest one being 64 mm. long. The males, as usual among vivi- 
parous fishes, were greatly in the minority, and much smaller, the 
largest one having a length of only 30 mm. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 299 

This species is recognized principally by the greenish color in 
life, and the black spots along the middle of the side, which may be 
quadrate, or vertically somewhat elongate, and which in nearly all 
the specimens from near El Valle are united on the posterior half 
or two- thirds of the body, forming a continuous black lateral band. 

The number of young in a brood seems to be small, but the 
broods probably are born at short intervals. For example, a female, 
33 mm. long, with a greatly distended abdomen, contained 8 large 
embryos with little yolk, and 12 smaller ones, already in the "eyed" 
stage, besides eggs of at least three different sizes. Another female, 
40 mm. long, but with the abdomen less distended than the one 
already mentioned, contained only 4 eggs with embryos, and 4 
very large eggs without embryos, besides 3 or 4 sets of smaller eggs. 

The intestinal tract is very short. The contents of two stomachs 
examined consisted of insect fragments. This fish probably is of 
value as a destroyer of mosquito larvae. Unfortunately it does not 
seem to have established itself in abundance in the artificial lakes 
of the Canal. Although Hubbs (1926, p. 47) reported "numerous 
specimens" from Gatun Lake, Barro Colorado Island, I did not take 
this fish there in two days of seining. I failed also to get it at several 
other places in Gatun Lake where collections were made, as well 
as in Miraflores Lake. 

This species, unlike its near relative, B. cascajalensis, seems to 

avoid brackish water, confining itself chiefly to somewhat higher 

^altitudes. It is reported from both slopes of central Panama, but 

not from the Bayano or Tuyra basins. On the Pacific slope of 

western Panama it is replaced by B. terrabensis. 

Brachyrhaphis cascajalensis (Meek and Hildebrand). 

Gambusia cascajalensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 86, 1913 Rio Cascajal, Porto Bello, Panama; p. 318, 1916. 

Specimens were collected at Puerto Pilon; Cativa; Largo Remo 
Island; Fort Sherman (Toro Point); in Gatun Lake at Gatun and 
Barro Colorado Island; and in a creek tributary to Gatun Lake, 
on the Madden Dam Road. In general the specimens run larger 
in size than those of Gambusia episcopi. Females of 50 mm. or more 
in length, and males 30 mm. and upward are common, the largest 
female taken being 63 mm. and the largest male 37 mm. long. 

This species has a rather more slender body than episcopi, as 
pointed out by us (1916, p. 318). The dorsal fin is more posteriorly 
placed, and apparently has fewer rays, its origin in females being 

ft 



300 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

over the end of the base of the anal instead of over the middle of 
the anal, as in episcopi. The number of rays is constantly 7 in 19 
specimens, whereas in episcopi this fin has constantly 8 rays ac- 
cording to 18 specimens examined, if in each species the last partly 
divided ray is counted as one. Furthermore, the dorsal profile is 
nearly straight in advance of dorsal instead of notably convex, as 
in episcopi. B. cascajalensis also is plainer in color, being grayish 
and without a lateral band or lateral spots, except in a few small 
specimens which have faint dark spots. The black on the anal 
is generally more prominent and spreads over more of the fin. 

The intestinal tract is as short as in episcopi. Two specimens 
examined had fed on insects. The species no doubt feeds on mos- 
quito larvae if available, and where numerous enough it probably 
provides a degree of mosquito control. Although taken in two 
places in Gatun Lake it did not seem to be numerous, and it was 
not found in Miraflores Lake. Therefore, it seems to be too rare 
in the artificial lakes of the Canal to be of much value in controlling 
mosquito-breeding. 

Comparatively large broods of young are apparently produced 
by large females, as a specimen 58 mm. long contained 49 large 
embryos. These embryos had absorbed nearly all the yolk and 
were pigmented almost like the adults. Therefore, they were, no 
doubt, about to be born. However, no other eggs with embryos 
were present in this specimen, nor in a smaller one examined, as 
found in several other species of this family here reported. The 
smaller female, 43 mm. long, contained only 13 large embryos, 
besides eggs of two or three different sizes. 

During the recent investigation this species was taken only in 
the Atlantic drainage. Earlier (1911 and 1912), a few specimens 
were taken in the Pacific drainage of central Panama. It was not 
secured in the Bayano nor Tuyra basin. Hubbs (1926, p. 47) 
reported it from pools and shallows in the Rio Nargana, a few miles 
from the Caribbean Sea, San Bias, Panama. He reported it also 
from several localities in the Caribbean drainage on both sides of 
the Panama-Costa Rica boundary. The last-mentioned record was 
based on specimens collected by Behre, which she also reported 
(1928, p. 315). This species, therefore, appears to inhabit the 
Atlantic slope of all of Panama and part of Costa Rica. It seems 
to be most numerous in lowland pools and streams, occurring at 
times in brackish water. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 301 

Brachyrhaphis terrabensis (Regan). 

Gambusia terrabensis Regan, Ann. Mag. Nat. Hist. (7), 19, p. 260, 1907; 
Biol. Cent. Amer., Pisces, p. 97, pi. 12, fig. 7, 1907 Rio Grande de Terraba, 
Pacific slope, Costa Rica. 

Specimens were collected in a muddy trickle on a mountain side, 
a short distance from the Rio Chiriqui Viejo, at an elevation of 
about 5,000 feet, in water less than an inch deep. No native fishes 
were seen above this elevation in that river basin, which was explored 
to an altitude of about 7,000 feet. Very brightly colored specimens 
were collected in quiet places in the clear water of the Rio Barilles 
(tributary of the Rio Chiriqui Viejo) at an elevation of about 4,800 
feet. Others were taken in the near-by lagunas Gulnar and Grande 
at about the same altitude. The largest female taken is 49 mm. 
and the largest male has the relatively great length of 42 mm. 

In shape of body and color, this species is similar to Gambusia 
episcopi. It is readily separable from that species, as well as from 
Brachyrhaphis cascajalensis, by the longer dorsal fin, which has 
13 rays. Its origin also is farther forward, being in advance of the 
anal in females. Because of the more anterior position of the dorsal 
only 8 or 9 series of scales are present between the upper angle of 
the gill opening and the origin of the dorsal, whereas 12 or 13 series 
may be counted in the other two Panama species of the genus. 

B. terrabensis is known only from the Pacific slope of western 
Panama and from Costa Rica. In addition to the specimens already 
listed here, Hubbs (1926, p. 43) recorded specimens from the upper 
part of the Rio Chiriqui del Tire Basin, and others from the vicinity 
of Boquete. These specimens also in part were listed by Behre 
(1928, p. 315). Still others from the same general vicinity of Panama 
were recorded by Hildebrand (1928, p. 83). 

Trigonophallus Hubbs. 

This genus seems to be close to Brachyrhaphis. It is described 
by Hubbs (1926, p. 48) in part as follows: "This organ (gono- 
podium) is longer than in Brachyrhaphis, being decidedly more than 
one- third as long as the fish (to caudal fin). The extreme mem- 
branous tip is peculiarly hardened and modified into a subtriangular 
structure, the free tips of which are pointed outward and backward. 
The distal segments of ray 3, as in neither of the related genera, are 
produced posteriorly as definite pointed spines. The tips of rays 
4 and 5, as in most of the species here referred to Brachyrhaphis, 
are slightly turned backward." 



302 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Trigonophallus punctifer Hubbs. 

Trigonophallus punctifer Hubbs, Misc. Pub. Mus. Zool., Univ. Michigan, No. 
16, p. 49, 1926 Guibari Creek, tributary of Rio Cricamola, Atlantic 
slope, western Panama. 

This species is known only from the type, a male 30 mm. long, 
and some female paratypes, 27 to 51 mm. long, collected in a tribu- 
tary to the Rio Cricamola and in the Rio Cricamola, both near 
Conquantu, and in the upper course of Western River, flowing into 
Almirante Bay, all from the Atlantic slope of western Panama. 
The type specimens are recorded also by Behre (1928, p. 316), 
who collected them. The species was not seen by me. The following 
description is condensed after Hubbs. 

Body moderately deep, rather sharply compressed posteriorly; 
dorsal contour almost straight from snout to occiput, from there to 
dorsal moderately convex; tail bent downward dorsally; head 3.3 
to 3.7; depth 3 to 3.4; snout 2.8 to 3.35 in head; eye 2.7 to 3.6; 
interorbital 1.9 to 2.5; caudal peduncle 1.6 to 1.9; mouth partly 
lateral, the cleft extending more than halfway to eye; maxillary 
reaching vertical from anterior margin of eye; symphysial knob of 
mandible protruding beyond upper jaw; teeth firmly fixed, sharply 
conical, in bands of moderate width, the outer ones enlarged; scales 
28 or 29 from upper angle of gill opening to base of caudal ; dorsal 
with 10 or 11 (rarely 9) rays, its origin nearly equidistant from tip 
of snout and end of middle rays of caudal; caudal truncate; anal 
with 9 rays (including unbranched ones), its origin slightly in 
advance of dorsal; ventrals not modified in males; pectoral rounded, 
1.3 to 1.5 in head. 

Color pale, with a suffusion of dark behind pectorals and on top 
of head; upper lip blackish; margin of mandible dusky; scale pockets 
on back and sides narrowly margined with dusky, the dark often 
intensified at apex, forming inconspicuous rows of dots. Dorsal fin 
with a row of vertically elongate spots on the membranes near the 
base, the outer posterior angle of fin dark; caudal dusky, especially 
toward margin; anal with a submedian blackish blotch. 

This species according to the published account seems to resemble 
Brachyrhaphis cascajalensis and B. episcopi. It differs from both, 
however, in the somewhat more numerous dorsal rays, approaching 
B. terrabensis in that respect. In the dark dots on the body it 
resembles Gambusia nicaraguensis, which contrary to the present 
species also has dark points on the dorsal and caudal fins. In the 
black blotch on the anal fin and the dark spots near the base of 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 303 

the dorsal it seems to agree with the species of Brachyrhaphis here 
discussed. 

Allogambusia Hubbs. 

Allogambusia Hubbs, Misc. Pub. Mus. Zool., Univ. Michigan, No. 13, p. 8, 
1924; No. 16, p. 56, 1926 (type Gambusia tridentiger Garman). 

This genus is described by Hubbs as follows: "Ray 3 (of gono- 
podium) with a short, suberect, curved spur near tip; anterior 
branch of ray 4 with a much enlarged node somewhat resembling 
the 'elbow' of the Gambusiini." 

Each jaw has an outer rather close-set series of teeth, followed 
by a definite band of minute ones; intestinal tract shorter than body; 
vertebrae about 13+19; intromittent organ (gonopodium) 2.4 to 
2.7 in standard length. 

The genera Allcgambusia, Darienichthys, and Panamichthys were 
all carved out of the genus Priapichthys as understood by Meek 
and Hildebrand (1916, p. 319). Therefore, the descriptions of the 
species, now placed in the three later genera, appear under the genus 
Priapichthys in the earlier work. 

Allogambusia tridentiger (Garman). 

Gambusia tridentiger Garman, Mem. Mus. Comp. Zool., 19, p. 89, pi. 4, fig. 10, 

1895, teeth only Isthmus of Panama. 
Priapichthys tridentiger Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 320, fig. 6, 1916. 

Many specimens of this species, ranging from 9 to 35 mm. in 
length, were preserved. The species was taken on the Pacific slope 
at El Valle; in coastal streams between Campana and La Venta; 
Rio Capira at Campana; creek at Albrook Landing Field; Rio 
Cocoli; Rio Pacora; and in swamps at the La Jagua Hunting Club. 
On the Atlantic side it was secured in Madden Lake at the mouth 
of the Boqueron; in a creek on Madden Dam Road, flowing into 
Gatun Lake; and in an abandoned reservoir at Mount Hope. This 
fish is numerous in some places, as in the swamps near the La Jagua 
Hunting Club. It does not seem to have established itself in the 
artificial lakes of the Canal, as it was not secured either in Gatun or 
Miraflores Lake. Madden Lake had just been formed when the 
specimens were collected at the mouth of the Boqueron, February 
12, 1935. This species was not seen in any of the locks of the Canal 
when dewatered in 1935 and 1937. 

The males are recognized readily by the long intromittent organ 
with its prominent spur near the apex, visible under comparatively 



304 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

low magnification. The peculiar structure of this organ is shown 
in figure 6 by Meek and Hildebrand (1916, p. 321). The females, 
however, are sometimes not readily distinguishable from those of 
Darienichthys dariensis (Priapichthys dariensis in Meek and Hilde- 
brand, 1916, p. 321). In general, the females of the present species 
have more prominent dark bars, but some specimens are scarcely 
distinguishable by the color. However, the dorsal fin is constantly 
a little more anteriorly placed in tridentiger, wherein its origin is 
over or slightly in advance of the base of the last ray of the anal, 
whereas in dariensis the origin of the dorsal is always somewhat 
posterior to the end of the base of the anal. Although the lateral 
series of scales is almost identical in number in these species, there 
is a difference in the number of scales in advance of the dorsal, due 
to the difference in position of the fin, tridentiger having 14 or 15 
series of scales between the upper angle of the gill opening and the 
origin of the dorsal, whereas dariensis has 17 or 18. The difference 
in the number of scales in advance of the dorsal also prevails in 
adult males, in which the anal fin is situated far in advance of the 
dorsal in both species. The differences in scale counts and position 
of the dorsal fin are not shown in our earlier publication (1916). 

It is unfortunate that this fish does not seem to have established 
itself in the artificial lakes of the Canal, as it is undoubtedly an 
enemy of the mosquito; first, because it lives in quiet waters where 
mosquitoes ordinarily breed; and, second, because it feeds on insect 
larvae, as shown by four intestinal tracts examined. 

The difference in size at which the anal fin of the male becomes 
fully modified and ready to serve as an intromittent organ is com- 
paratively great for such a small fish. Males fully mature at a 
length of 16 mm. have been observed, whereas others at a length of 
22 mm. are still immature. In this species, as in many others of 
this family, the male is much smaller than the female, the largest 
male in the present collection being 25 mm. long, whereas the 
largest female has a length of 35 mm., though a female 45 mm. 
long has been reported. 

The young are born at a comparatively large size, fully scaled, 
and pigmented. Young 6 mm. long were removed from the parent. 
These fish were fully scaled, and had the color of young free-swim- 
ming fish, including a dark lateral line and a black spot on the 
middle of the side above the base of the anal. Apparently the broods 
are rather small, but seemingly are born in quick succession. The 
largest number of embryos found, in four specimens dissected, 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 305 

was 17 in a female 35 mm. long, whereas a female 22 mm. long 
contained only 6. One specimen containing large embryos, which 
had absorbed nearly all the yolk and were undoubtedly about to be 
born, also contained a set of eggs with smaller, but well-formed 
embryos, besides less mature eggs. Eggs in at least three different 
stages of development were present in all examples examined. 

The range of this species, so far as known, is limited to the 
Atlantic and Pacific slopes of central and eastern Panama, or to 
central Panama, if Allogambusia cana (Meek and Hildebrand) from 
the Tuyra Basin is a distinct species, as considered by Breder (1927, 
p. 133). 

Darienichthys Hubbs. 

Darienichthys Hubbs, Misc. Pub. Mus. Zool., Univ. Michigan, No. 13, p. 8, 
1924; No. 16, p. 61, 1926 (type Gambusia dariensis Meek and Hildebrand). 

This genus is described by Hubbs as follows :"Gonopodium 
rather short, between two-fifths and one-third standard length of 
body; process at tip of ray 3 more or less retrorse to axis of gono- 
podium; serrae of posterior branch of ray 4 weak (but more numer- 
ous than shown in Meek and Hildebrand's figure)." 

Each jaw has an outer series of close-set teeth, followed by a 
more or less definite band of very minute teeth; intestinal tract very 
short, not as long as body; vertebrae about 13+20; intromittent 
organ (gonopodium) 2.7 to 2.9 in standard length. 

Darienichthys dariensis (Meek and Hildebrand). 

Gambusia dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 88, 1913 Rio Capetf, tributary of the Tuyra. 

Priapichthys dariensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 321, fig. 7, 1916. 

This fish was taken in only two collections during the 1935 and 
1937 investigations, namely, those from coastal streams between 
Campana and La Venta, and from the Rio Pacora. Fifty-three 
specimens, ranging in length from 12 to 38 mm., are at hand. 

Although this species has been considered generically distinct 
by some recent writers, the females are not always easily distinguish- 
able from Allogambusia tridentiger, as pointed out in the account of 
that species. The males are readily distinguishable by the structure 
of the intromittent organ. In the present species one of the seg- 
ments of a produced ray is recurved and directed forward, as shown 
by Meek and Hildebrand (1916, p. 322, fig. 7). Although the 
females generally are plainer in color than those of A. tridentiger, 



306 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

often having no crossbars, the males have more numerous and 
more distinct dark bars in the present species. The larger number 
of rows of scales between the upper angle of the gill opening and the 
origin of the dorsal, which is 17 or 18, is generally sufficient to 
separate this species from A. tridentiger. Then, too, in females the 
relative position of the dorsal and anal is different, for in the present 
species the dorsal begins well behind the end of the base of the 
anal, whereas in tridentiger it begins over or very slightly behind 
the base of the anal. The differences just mentioned are not in- 
cluded in our earlier publication. 

This species is known only from the Pacific slope of central 
and eastern Panama. In earlier investigatiDns it was taken only 
in the Rio Juan Diaz, Rio Bayano and Rio Tuyra. The range is 
now extended to coastal streams between Campana and La Venta. 
Breder (1927, p. 133) reported it common in the Chucunaque Basin. 
It has not yet been found on the Canal Zone. 

Panamichthys Hubbs. 

The gonopodium is comparatively simple, having no horn-like 
hooks distally. The tip of this organ is curved abruptly forward 
to form a sort of hook, which is composed of the closely joined rays 
4 and 5. Only ray 4 has a few serrae on its posterior edge, behind 
which ray 5 is arched somewhat backward (see Meek and Hildebrand, 
1916, p. 323, fig. 8). 

Panamichthys panamensis (Meek and Hildebrand). 

Priapichthys panamensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 322, fig. 8, 1916 Chame Point, Panama. 

This species was made the type of a new genus by Hubbs (1924, 
p. 8). The characters upon which the genus was based are set forth 
in the generic account and are shown in the figure accompanying our 
original description. 

Although a specimen was taken in the Rio Chame in 1911, the 
species was not found in 1937, when another collection was made 
in that river. 

A mistake was made in our original description in giving the 
position of the dorsal fin. This fin, instead of having its origin 
"midway between posterior margin of the eye and base of caudal," 
actually originates midway between the posterior margin of the eye 
and the end of the caudal. 

The species is known only from the type material collected in the 
Rio Chame, near Chame, and in a brackish pool on Chame Point. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBR AND 307 

Poeciliopsis Regan. 

This genus was divided into smaller genera by Hubbs (1926, 63 
and 69), who made P. elongatus the type of a new genus, Aulophallus, 
which was based principally upon the structure of the mouth, teeth, 
and intromittent organ or gonopodium. The mouth was described as 
transverse, that is, without lateral cleft; the teeth as in a single series, 
hooked inward, very long, hair-like and loose; and the gonopodium 
"without the 'crescentic horn' (of some other genera) in membranous 
tip; none of the segments consolidated ; two halves of posterior branch 
of ray 4 closely united, bearing an apparently single series of thorn- 
shaped serrae; segments of anterior branch of ray 5 more oblique, and 
greatly widened, as though in compensation for lack of specialization 
of ray 4." I have no special objection to this division of the genus. 
However, for convenience and brevity, the following accounts are 
given under the generic name appearing in our earlier publication 
(1916, pp. 324-326). 

Hubbs (1926, p. 69) said, "In agreement with Giinther and in 
disagreement with Steindachner and Meek and Hildebrand, I find 
but one row of teeth in elongatus; the latter authors have seemingly 
mistaken some of the fine buccal papillae for teeth." I have removed 
jaws and teeth from 3 specimens, 1 male and 2 females, in the present 
collection, and have dried the jaws, to shrink the soft tissues, that 
the teeth might stand out more prominently. Minute teeth are 
unmistakably present behind the outer enlarged series in each jaw 
in the three specimens especially treated and examined. The teeth 
are similar in shape to the outer ones, but so much smaller that they 
could be easily overlooked. 

Poeciliopsis elongatus (Giinther). 

Poedlia elongata Giinther, Cat. Fish. Brit. Mus., 6, p. 342, 1866 Panama. 
Poeciliopsis elongatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 324, fig. 9, 1916. 

This species is represented by 81 specimens, ranging from 18 to 
140 mm. in length. Many others were taken but not preserved. It 
is common to numerous in salt and brackish water and ranges to 
fresh water, which it apparently scarcely enters. The specimens at 
hand were taken at Farfan Beach in the mouth of a tidal stream, and 
in the hull of a sunken vessel, which was under water at high tide, but 
exposed and dry except for small pools within the hull at low tide. 
Numerous individuals of this species occupied the pools in the hull. 
It was also taken in small coastal streams between Campana and La 
Venta, and many individuals were stranded or occupied the "man 



308 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

holes" in the floor of Miraflores Locks, in both the upper and lower 
chambers of the west side, when dewatered in 1937. As none were 
seen or taken in Pedro Miguel Locks, it would appear that this fish 
does not advance so far into fresh water. 

The chief recognition marks are the rather long slender body, a 
moderately depressed head, transverse mouth, and the position of 
the dorsal and anal fins, which are placed opposite each other, the 
dorsal, however, beginning a little behind the origin of the anal in 
the young, as well as in adult females. In adult males the anal fin 
is greatly modified; it is far in advance of the dorsal and some of the 
rays are greatly produced, much longer than head, forming of course 
the intromittent organ, which is not prominently provided with 
hooks as in most other species of this family. A camera lucida 
tracing of this organ is shown by Meek and Hildebrand (1916, p. 325, 
fig. 9) ; the ventral fins are unmodified in males. Large females often 
are plain grayish, but smaller specimens, and especially the males, 
have black crossbars on the posterior part of the body. In the 
young the bars are fewer, far apart, intensely black, and present 
anteriorly as well as posteriorly. 

The fish appear to be largely herbivorous, judging from the 
contents of three stomachs examined and by the weak hair-like 
teeth. The alimentary canal, however, is not long or convoluted as 
in most herbivorous species. The teeth consist of an outer row of 
very slender movable teeth curved inward, followed by extremely 
minute teeth of similar shape. The jaws are very weak. 

The young are born at a large size. Examples removed from the 
ovary of a female, 140 mm. long, had attained a length of 16 mm. 
They were fully scaled, and already had 4 or 5 black crossbars. 
The fish undoubtedly are born about this size, as free-swimming 
specimens only 18 mm. long were taken. In addition to 16 large 
embryos, the 140 mm. fish contained 35 younger embryos, all already 
in the "eyed stage," and about 7 mm. long, as well as some large eggs. 
A smaller female, 90 mm. long, contained five large embryos, and 
five smaller ones in the "eyed stage"; also some large eggs. The 
indications are that the broods are born in rapid succession, but that 
the number in a brood is considerably smaller than in some of the 
other species of the family, as, for example, in Gambusia affinis of 
the United States, in which broods of 50 are common, and broods 
of upward of 100 or even 200 have been found. 

This top-minnow reaches a comparatively large size, females 
150 mm. long and males 60 mm. long having been taken in Panama. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 309 

This species is apparently confined to the Pacific coast of Costa 
Rica and western and central Panama. It has not been reported 
from as far east as the Tuyra Basin. 

Poeciliopsis pittieri (Meek). 

Poecilia pittieri Meek, Field Mus. Nat. Hist., Zool. Ser., 10, p. 71, 1912 La 
Junta, Costa Rica. 

Poeciliopsis isthmensis Regan, of which an account was given in 
our earlier work (1916, p. 325), though not taken by us, was synony- 
mized with P. pittieri Meek, by Hubbs (1926, p. 70), who placed 
the species in his new genus Phallichthys, also carved out of the older 
genus Poeciliopsis. Behre secured specimens in Costa Rica and also 
in the Atlantic drainage of extreme western Panama, which were 
listed by Hubbs (1926, p. 71) and by Behre (1928, p. 316). Breder 
(1925, p. 141) "questionably referred to this species" a young female 
taken in a foul drainage ditch below Gatun Spillway. Having 
collected rather extensively in 1911 and 1912, and again in 1935 and 
1937, in the vicinity of Colon, from whence the types of P. isthmensis 
were reported, I am obliged to conclude that the species either is 
very rare there, or that a mistake was made in the earlier record. 
However, the species now unquestionably belongs to the fauna of 
Panama on the basis of specimens collected in western Panama, to 
which reference has been made. 

Poeciliopsis retropinna (Regan). 

Poecilia retropinna Regan, Ann. Mag. Nat. Hist., (8), 2, p. 458, 1908 

Brocura, Costa Rica. 

Aulophallus retropinna Hubbs, Misc. Pub. Mus. Zool., Univ. Michigan, No. 16, 
p. 69, 1926. 

Head 4.5; depth 3.5; D. 9; A. 10; scales 30; snout as long as eye, 
3.5 in head; origin of dorsal equidistant from front of eye and end of 
caudal fin; caudal rounded; origin of anal a little in advance of dorsal; 
pectorals nearly as long as head. Color olivaceous; scales with dark 
edges; fins pale (condensed after Regan). 

A single specimen, a female 77 mm. long, was known until Hubbs 
(1926, p. 69) reported it from some tributaries of the Rio Chiriqui 
del Tire, Pacific slope of western Panama, from specimens collected 
by Behre, which she also listed (1928, p. 316). Hubbs found the 
structure of the gonopodium identical with that of elongatus, and 
placed it in his new genus Aulophallus with elongatus. 

This species seems to differ from elongatus, as far as may be 
judged from the inadequate accounts, principally in the plainer 



310 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

color, no crossbars or spots being present. It may be noted here, 
however, that large females of elongatus, too, are without bars. The 
habitats seem to differ, as elongatus lives in lowlands and brackish 
water, whereas retropinna was taken in the mountains of western 
Panama. 

Mollienisia Le Sueur. 

This genus is characterized principally as follows: body moderately 
robust, compressed posteriorly; mouth small, transverse, with weak 
teeth in bands in the jaws, the outer ones enlarged and movable; 
intromittent organ short, preceded by a membranous hood, distally 
with an antrorse and a retrorse hook; ventral fins modified in males, 
the first articulated ray being produced. The dorsal fin is sometimes 
very high in adult males. 

Four species were listed in our earlier work (1916, pp. 326-330) 
under this genus. Two of those listed, namely, formosa from Colon, 
and cuneata from Turbo, Gulf of Darien, had not been taken by us, 
and have not been secured by collectors since that time. However, 
Breder (1927, p. 135) took caucana (made the type of a new genus, 
Allopoecilia, by Hubbs, 1924, p. 11), in small tributaries of the Rio 
Sucubti (Tuyra Basin), Darien, Panama. 

Mollienisia sphenops (Cuvier and Valenciennes). 

Poecilia sphenops Cuvier and Valenciennes, Hist. Nat. Poiss., 18, p. 130, pi. 526, 

1846 Vera Cruz, Mexico. 
Mollienisia sphenops Meek and Hildebrand, Field Mus. Nat. Hist., Zool/ 

Ser., 10, p. 326, fig. 10, 1916. 

Numerous specimens of this common fish were preserved. It was 
taken on the Pacific slope in swamps at the La Jagua Hunting Club; 
in the Rio Pacora and the Rio Cabra; at Fort Kobbe; and in Mira- 
flores Lake and the Rio Cocoli, a short distance above the lake. On 
the Atlantic side it was taken at Puerto Pilon; Largo Remo Island; 
Cativa; Fort Sherman (Toro Point); Mount Hope; in several places 
in Gatun Lake (including Barro Colorado Island) ; in a small stream 
on Madden Dam Road; and in Madden Lake, at the mouth of the 
Boqueron. Next to Astyanax ruberrimus, it is the most numerous 
fish in the waters of Panama. It ranges from lowland brackish water 
swamps and streams (being able to endure more salt than A. ruber- 
rimus) to upland rivers and creeks, generally occupying quiet, 
shallow water. Large males, with high dorsal fins with black spots, 
and generally with blue, greenish, and silvery iridescence are prized 
as "pet fish" and a limited number are shipped to Europe for use 
in aquariums. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 311 

The species is adequately described by Meek and Hildebrand 
(1916, p. 326). The chief recognition marks are the depressed head, 
robust body, and deep, strongly compressed tail. The dorsal and 
anal fins are opposite each other in the young and adult females, the 
former beginning a little in advance of the latter, and always marked 
with dark dots or blotches. In adult males the anal fin moves far 
forward in the course of development, becoming situated consider- 
ably in advance of the dorsal. It is modified to serve as an intro- 
mittent organ (gonopodium) for the transfer of the sperms from the 
male to the female. The members of this genus differ notably from 
other local forms, except Alfaro, in the structure of this organ, which 
is covered or preceded distally by a sort of membranous hood. The 
structure is figured by Meek and Hildebrand (1916, p. 328, fig. 10). 
The ventral fins, too, are modified in adult males, the first (outer) 
articulated ray being produced. The dorsal fin in some males, at 
least, becomes greatly elevated. 

As the Atlantic and Pacific slope members of M. sphenops cannot 
be distinguished, it is impossible to determine from specimens if 
intermingling has taken place through the Canal. However, there 
is apparently nothing to prevent it. Nevertheless, this fish was not 
taken in the locks. 

The great difference in the size of the males at which the anal 
fin becomes fully modified, and ready to function as an intromittent 
organ, is remarkable. For example, a male only 32 mm. long has 
the organ fully developed, whereas in another male 55 mm. long it 
is still immature. Although males do not seem to grow quite as 
large as females, the disparity is not as great as in most groups of this 
family. Females 100 mm. long, and males upward of 75 mm., have 
been taken in Panama. 

Although this fish generally occupies areas suitable for mosquito- 
breeding, it probably is not a very effective enemy of the mosquito, 
as it tends too much to feed on algae. 

Attempts have been made to split up sphenops from different 
areas into species or subspecies. However, insufficient work has 
been done to demonstrate the divisions, if indeed they exist. As 
now understood the species may be regarded as ranging from Mexico, 
on both slopes of Panama to Colombia. Meek and Hildebrand did 
not take it in the Tuyra Basin, but Breder (1927, p. 134) recorded it 
from there, having taken it in the headwaters of the Rio Sucubti and 
its tributaries. 



312 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Mollienisia caucana (Steindachner). 

Girardinus caucana Steindachner, Denkschr. Akad. Wiss., Wien, 42, p. 87, 

pi. 6, figs. 4, 5, 1880 Caceres, Colombia. 
Mollienisia caucana Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 329, 1916. 

This species is known in Panama only from the Tuyra Basin, 
where we collected it in 1912 in a few of the upper tributaries of the 
Rio Tuyra, and where Breder later collected specimens in small 
tributaries of the Rio Chucunaque, which he recorded (1927, p. 135) 
as Allopoecilia caucana. 

Although this species has been made the type of a new genus, 
Allopoecilia (Hubbs, 1924, p. 11), the writer prefers to leave it with 
Mollienisia, as the differences in the structure of the gonopodium, 
upon which the new genus was based, appear too trivial to constitute 
generic characters. The two species, sphenops and caucana, indeed 
are closely related, as shown in our earlier work (1916, p. 329). 

This species is known from the Tuyra Basin, Pacific slope in 
eastern Panama, and from the Atlantic slope of Colombia. 

Mollienisia cuneata (Garman). 

Poecilia cuneata Garman, Mem. Mus. Comp. Zool., 19, p. 62, pi. 5, fig. 3, 

1895 Turbo, Gulf of Darien. 
Mollienisia cuneata Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 329, 1916. 

This species, regarded by Hubbs (1926, p. 77) as a subspecies of 
M . sphenops, was included in our earlier work on the basis of its 
description from Turbo, Gulf of Darien. It has not been taken in 
Panama by recent collectors. Hubbs (loc. cit.) considers Colombian 
material as belonging to cuneata. 

Mollienisia formosa (Girard). 

Limia formosa Girard, Proc. Acad. Nat. Sci. Phila., p. 115, 1859 Palo Alto, 

Mexico. 
Mollienisia formosa Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 330, 1916. 

This species was included in our earlier work on the basis of a 
record by Regan (1913, p. 1012), who listed it from Colon. It has 
not been taken in Panama by recent collectors. 

Hubbs and Hubbs (1932, pp. 628-630) have claimed that M. 
formosa is a hybrid, resulting from a cross between sphenops and 
latipinna. If that be true, formosa could not occur in Panama, 
as latipinna does not range southward to the Isthmus of Panama. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 313 

The habitat of M. formosa generally has been given as the 
Atlantic slope of Mexico and Central America. 

Alfaro Meek. 

This genus differs from all other genera of this family known 
from Panama in the presence of a sharp keel along the lower edge of 
the caudal peduncle, the keel being formed by a double series of 
paired scales. The intromittent organ is somewhat similar to that 
of Mollienisia, being short and preceded or covered anteriorly by a 
membranous hood. Unlike Mollienisia, however, it is without hooks 
or retrorse spines. 

This genus is not included in our earlier work. It is added here 
on the basis of specimens collected on the Atlantic slope of extreme 
western Panama, as shown subsequently. 

Alfaro cultratus (Regan). 

Petalosa cultratum Regan, Ann. Mag. Nat. Hist,, (8), 2, p. 458, 1908 Rio 
Iroquois, Costa Rica. 

This species belongs to the fauna of Panama on the basis of 
specimens collected on the Atlantic slope of extreme western Panama 
by Dr. E. H. Behre. These specimens were recorded by Hubbs 
(1926, p. 79) and by Behre (1928, p. 317). 

Head 3.8 to 4.3; depth 3.1 to 3.7; D. 7 or 8; A. 9 or 10; scales 
32 to 34. Body much compressed, profile from nape to dorsal 
straight; head flat above; snout 2.7 to 3.2 in head; eye 2.7 to 3.1; 
dorsal fin on posterior third of body; pectorals broad, 1.2 to 1.4 in 
head. Color olivaceous, no spots or bars; vertical fins slightly dusky 
(condensed after Meek's description of A. acutiveniralis, a synonym 
of cultratus). 

This species differs from all other species of the family known 
from Panama, in the sharp keel along the lower edge of the caudal 
peduncle, formed by double series of paired scales, which is a charac- 
ter considered of generic importance. 

Family CYPRINODONTIDAE 

Body elongate, compressed, at least posteriorly; mouth small, 
terminal; premaxillaries protractile; teeth pointed or more or less 
incisor-like; gill membranes united, free from the isthmus; gill rakers 
short and thick; scales moderately large, cycloid; no lateral line; 
dorsal fin single, with soft rays only; caudal square to more or less 
pointed, not forked; anal somewhat similar to dorsal, not modified 
in male; ventrals abdominal, species oviparous. 



314 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

A single genus is known from Panama, namely, Rivulus, which 
was included in the family Poeciliidae in our earlier work. The 
oviparous species now are separated from the viviporous ones under 
the family name appearing herewith by nearly all ichthylogists. 

Rivulus Poey. 

The fishes of this genus are slender, generally depressed anter- 
iorly, but always compressed posteriorly. The head is low and flat 
above; the mouth is small and forms a vertical groove in front of the 
very narrow preorbital; the teeth are villiform, generally present 
on the vomer and always in bands in each jaw, the outer ones gener- 
ally being somewhat enlarged. The fins are rounded; the caudal is 
square to pointed, and occasionally more or less notched at the end 
of the upper or lower rays in males. The dorsal is small and is inserted 
far back over the posterior part of the much longer anal. The color- 
ation generally is rather plain, the females often having an ocellus 
at the base of the upper caudal rays. 

The species are very slimy when removed from the water. They 
are difficult to seine, as they seem to escape by clinging close to the 
bottom, or by finding protection under or among objects in the 
water. Many more fish were seen in pools in a creek on Barro 
Colorado Island, Canal Zone, for example, than were captured by 
repeated seining. 

Only two species of this genus were included in our earlier work. 
The number of species found has increased to five, two of which ap- 
parently require names. Because of the additions made, a key to the 
species is introduced. 

KEY TO SPECIES OF RIVULUS 

a. Caudal fin broadly rounded to nearly square. 

b. Scales rather large, 33 to 40 in lateral series between upper angle of gill 
opening and base of caudal, 7 or 8 complete longitudinal rows between 
bases of dorsal and anal. 

c. Body moderately robust, depth 4.5 to 5.2, and depth of caudal peduncle 

7 to 7.75 in standard length in adults; scales 33 to 37; general color 

brownish brunneus. 

cc. Body slender, depth 5.5 to 6, and depth of caudal peduncle 8.2 to 9 in 

standard length; scales 38 to 40; general color bluish.. . .chucunaque. 

bb. Scales smaller, 42 to 45 in lateral series between upper angle of gill opening 

and base of caudal, 10 or 11 complete rows between bases of dorsal and 

anal. 

d. Head only moderately depressed, not much broader than deep, its 

greatest width 1.4 to 1.5 in its length; interorbital 3.3 to 3.9 in head; 
pectorals rather long, reaching about three-fourths to ventrals; 
color brownish, with pale markings; vertical fins with black spots. 

volcanus, sp. nov. 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 315 

dd. Head strongly depressed, notably broader than deep, its greatest 
width 1.3 in its length; interorbital 2.9 in head; pectorals short, 
reaching only halfway to ventrals; color plain, scales slightly 

dark-edged; vertical fins plain or with light spots hildebrandi. 

oo. Caudal fin moderately pointed; body slender, depth 5 to 6, and depth of 
peduncle 7.6 to 8.6 in standard length; scales 33 to 38 in lateral series, 
between upper angle of gill opening and base of dorsal, 8 or 9 complete 
longitudinal series between bases of dorsal and anal . . . montium, sp. nov. 

Rivulus brunneus Meek and Hildebrand. 

Rivulus brunneus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 86, 1913 Toro Point, Canal Zone; ibid., p. 331, 1916. 

Six specimens, ranging in length from 18 to 50 mm., were col- 
lected in pools left in a creek near the end of the dry season, on 
Barro Colorado Island. 

The following measurements and counts are based on four speci- 
mens taken on Barro Colorado Island, and on four paratypes. Head 




FIG. 7. Rivulus brunneus Meek and Hildebrand. Male specimen, 50 mm. 
long. (From drawing by Andrew Pizzini.) 

3.4 to 4.1; depth 4.5 to 5.2; D. 9 or 10; A. 12 to 14; scales 33 to 37, 
complete rows between bases of dorsal and anal 7 or 8. Eye 3.5 to 
3.75 in head; interorbital 2.8 to 3.2; caudal peduncle 1.9 to 2.2 in 
head, or 7 to 7.75 in standard length; pectoral 1.5 to 1.7 in head. 
Ventrals fully as long as eye, reaching vent. 

This species is known only from the Atlantic slope of the Canal 
Zone, where it inhabits small creeks. 

Rivulus chucunaque Breder. 

Rivulus chucunaque Breder, Amer. Mus. Nat. Hist., Nov., No. 180, p. 7, fig. 
6,,1925 Rio Chucunaque Basin, Darien, Panama; Bull. Amer. Mus. Nat. 
Hist., 57, p. 135, fig. 8, 1927. 

This species was described from specimens taken in a small side 
stream of the Rio Chucunaque, Darien, by Breder. I have made a 
direct comparison of paratypes of this species and paratypes of 
brunneus. These species are closely related, as suggested by Breder, 



316 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

who stated that the chief difference seemed to be that of color, 
brunneus being brownish with black dots, which are faint on the 
dorsal and caudal fins, whereas chucunaque is pale bluish, sprinkled 
with pink dots forming more or less distinct lines along the rows of 
scales, having no caudal ocellus, the dorsal and caudal being pro- 
fusely marked with dark spots. 

Upon comparison of specimens of equal size it is evident that 
chucunaque is a more slender fish. Proportional measurements over- 
lap partly because small specimens (juveniles) are more slender than 
large ones. In four paratypes of chucunaque ranging in length from 
38 to 45 mm., the depth is contained in the standard length 5.5 to 6 
times, and the caudal peduncle 8.2 to 9 times, whereas in five speci- 
mens of brunneus, ranging in length from 40 to 50 mm., the same 
proportions are, respectively, 4.5 to 5.2, and 7 to 7.75. 

The average number of oblique rows of scales between the upper 
anterior angle of the gill opening and the base of the caudal seems to 
be somewhat greater in chucunaque. The number in four paratypes 
counted ranges from 38 to 40, whereas in eight specimens (including 
four paratypes) of brunneus the range is from 33 to 37. 

Mr. Breder recognized a subspecies of chucunaque, naming it 
sucubti, the type material having been taken in a small side stream 
of the Rio Sucubti, Darien. This subspecies is slightly more robust 
than the typical subspecies, according to Mr. Breder, though that 
is not evident from the particular paratypes examined, the ventral 
and vertical fins tend to be longer, and the dark spots on the dorsal, 
caudal, and anal fewer and larger. In general, this subspecies seems 
to be rather closer to brunneus than the typical subspecies. 

R. chucunaque, including both subspecies, is known only from the 
type material from the Chucunaque Basin, Darien, Panama. 

Rivulus volcanus sp. nov. 

Riwliis isthmensis Hildebrand (not Garman), Copeia, No. 168, p. 84, 1928 
Lagunas Verde, Grande, and Gulnar, Chiriqui, Panama. 

Type from Laguna Grande (or Davis), Chiriqui, Panama. 
No. 106509 United States National Museum. Male. Length 44 mm. 

Description of the type. Head 3.7; depth 5.8; D. 9; A. 14; scales 
(oblique series between upper angle of gill opening and base of 
caudal) 45, complete longitudinal rows between bases of dorsal and 
anal 11. 

Body slender, scarcely depressed anteriorly, compressed poster- 
iorly; caudal peduncle strongly compressed, 8.1 in standard length, 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 317 

2.2 in head; head moderately depressed, somewhat broader than 
deep, its greatest width 1.5 in its length; snout moderately short, 

4.3 in head; eye wholly lateral, 3.6; interorbital (bone) about equal 
to diameter of eye; scales small, rather difficult to enumerate, en- 
larged on head, reduced on chest, extending somewhat on base of 
caudal; dorsal small, the rays reaching first rudimentary ray of 
caudal, its origin about over beginning of last third of anal; caudal 
broadly and evenly rounded, about as long as head; anal rather 
long, ending nearly under middle of base of dorsal; ventrals small, 
scarcely as long as eye, failing to reach vent; pectorals broadly rounded 
like the caudal, reaching nearly three-fourths the distance to the 
ventrals, 1.6 in head. 

Color of preserved specimen brownish above, pale below; the 
brownish color broken somewhat by irregular pale markings; dorsal, 
caudal, and anal all marked with dark spots, the ones on margin of 




FIG. 8. Rivulus volcanus sp. nov. Type, male, 44 mm. long. (From drawing by 
Andrew Pizzini.) 

anal tending to coalesce, forming a dark border; ventrals and pec- 
torals plain. 

Variations within the species, as shown by the paratypes, are as 
follows (measurements and counts are based on nine specimens, 
unless otherwise stated, ranging in length from 35 to 44 mm.) : Head 
3.7 to 4.1; depth 5 to 5.8; D. 9 or 10; A. 13 to 15 (13 in 3, 14 in 10, 
and 15 in 4 specimens) ; scales (oblique series between upper angle of 
gill opening and base of caudal) 42 to 45, complete longitudinal 
series between bases of dorsal and anal 10 or 11. Snout 4.3 to 5.2 in 
head; eye 3.3 to 3.7 interorbital (bone) 3.3 to 3.9; width of head 1.4 
to 1.5; caudal peduncle 2.2 to 2.6; pectoral 1.5 to 1.6. 

The females, which are greatly in the majority in the col- 
lection, in general appear to be a little more robust than the males 
and the vertical fins are a little lower. They are a little lighter in 
color, have a definite ocellus on the upper part of the base of the 
caudal, and some of them have the anal definitely margined with 



318 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

black. The spotting on the vertical fins is the same as in males, 
except that in a few females the black dots form indefinite and 
irregular bars. A fresh specimen is described in my field notes as 
grayish green above, and pale to orange below. 

This species differs from hildebrandi, recorded from the same 
general vicinity, namely, Boquete, Panama, in being less robust, in 
having a narrower and less depressed head, longer snout, narrower 
interorbital, longer pectoral, and being less plain in coloration. 

The specimens were compared, also, with specimens in the 
National Museum identified as isthmensis, taken at San Jos (the 
type locality of isthmensis}, Miravalles, and Ochomago, Costa Rica. 
The Panama specimens are near relatives of this Costa Rican 
species, but the former differ in (a) the more slender body, (6) 
narrower head, (c) more numerous scales, and (d) in having the 
body light-spotted instead of dark-spotted. Most of the Costa 
Rican specimens have enlarged black spots on the sides posterior 
to the pectorals. Though the vertical fins are dark-spotted in both 
species, the spotting is finer and more profuse in the Panama speci- 
mens. The following proportions are based on 8 and the counts 
on 12 specimens of isthmensis: Head 3.6 to 4.1; depth 4.1 to 4.8; 
D. 8 or 9; A. about evenly 13 or 14; scales 35 to 39, longitudinal 
rows between dorsal and anal 8 or 9. Snout 4.5 to 5.3 in head; 
eye 3.6 to 4.2; interorbital (bone) 2.6 to 3; caudal peduncle 2 to 2.1; 
pectoral 1.5 to 1.75. 

The present collection contains 40 specimens, ranging in length 
from 12 to 44 mm., consisting of 3 males, 33 females, and 4 juveniles. 
A few of these specimens were seined in Laguna Gulnar, the rest 
in a shallow weedy cove of Laguna Grande, where the species was 
common. These lakes are at an elevation of about 4,500 feet, and 
supposedly occupy extinct volcanic craters. In addition, the speci- 
mens (not in good condition now), reported upon by me as isthmensis 
(1928, p. 84) from Chiriqui, were re-examined. This lot contains a 
specimen 76 mm. long, therefore much larger than any secured recently. 

The species is named volcanus after the volcanic lakes in which 
it lives. The name, Volcan, also is applied to the general vicinity 
in which the lakes occur. 

Rivulus hildebrandi Myers. 

Rivulus hildebrandi Myers, Ann. Mag. Nat. Hist., (9), 19, p. 123, 1927 
Boquete, Chiriqui, Panama. 

This species differs from other species from Panama according 
to the examination and direct comparison, of a paratype, a male 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 319 

60 mm. long (U.S.N.M. No. 92958), in (a) the robust body, which is 
depressed anteriorly; (6) the very short, broad head; (c) the very 
short, blunt snout; (d) the broad interorbital; () the short pectoral, 
which reaches only half the distance to the base of the ventral ; and 
(/) the rather plain coloration, the scales being slightly dark edged, 
the dorsal, caudal, and anal being faintly light-spotted, the last 
having a dark margin. The original description states that the 
fins in females are plain, and have a small ocellus on the upper 
part of the base of the caudal. 

The following proportions and counts are based on the paratype 
examined: Head 4.25 in standard length, depth 4.75; caudal peduncle 
7.25; predorsal length 1.35; pectoral 6.5; D. 9; A. 12; scales in 42 
oblique series between upper anterior angle of gill opening and base 
of caudal, and 11 complete longitudinal rows between the bases of 
the dorsal and anal. The scale counts in lateral series are given as 
49 to 50 in the original description. The difference may result 
from the place the counts are made. Myers may have counted 
from the occiput, whereas I counted from the upper angle of the 
gill opening. Snout about 4.6 in head; eye 3.3; interorbital (bone) 
2.9; width of head 1.3; caudal peduncle 1.8; pectoral 1.55. Ventrals 
a little shorter than diameter of eye, reaching only half the distance 
to vent; origin of dorsal slightly posterior to middle of base of anal. 

This species is known only from the type specimens from Boquete, 
Chiriqui, Panama. 

Rivulus montium sp. nov. 

Rivulus elegans Meek and Hildebrand (not Steindachner), Field Mus. Nat. 
Hist., Zool. Ser., 10, p. 331, 1916. 

Type from a hillside trickle between Rio Boqueron and Rio 
Pequeni, (Chagres Basin), Panama. No. 34880 Museum of Com- 
parative Zoology. Total length 63 mm., standard length 50 mm. 

Description of the type. Head 3.8; depth 5.25; D. 9; A. 12; 
scales (oblique series between upper angle of gill opening and base 
of caudal) 38, complete longitudinal rows between bases of dorsal 
and anal 9. 

Body about as broad as high anteriorly, strongly compressed 
posteriorly; depth of caudal peduncle 8 in standard length, 2.1 in 
head; head depressed, notably broader than deep, its greatest width 
1.55, and its depth 1.9 in its length; snout broader than long, its 
length 4.3 in head; eye lateral, 4.35, interorbital 3.25; scales in 
regular series, enlarged on head, somewhat reduced on chest, and 
extending on basal third of caudal; dorsal rather high, the rays 



320 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

graduated, next to the last one longest, reaching nearly to rudi- 
mentary rays of caudal, its origin over middle of base of anal; 
caudal fin long, not notched, moderately pointed, the middle rays 
longest, about as long as head; anal rather high posteriorly, the 
longest rays equal to those of dorsal, and as long as postorbital part 
of head, its base ending slightly in advance of end of base of dorsal; 
ventrals scarcely longer than eye, reaching almost to vent; pectorals 
with rounded margins, reaching only slightly more than half the 
distance to base of ventrals, 1.75 in head. 

Color grayish brown above, pale gray underneath; posterior 
half of sides with inconspicuous dusky spots. The vertical fins 
somewhat darker than the upper parts of the body; dorsal and 
anal with dark spots which are inconspicuously present on the base 
of the caudal also. Ventrals pale, with dusky outer margins; pec- 
torals slightly dusky, especially distally. 

The variation within the species, as shown by the type and six 
paratypes ranging in length from 32 to 53 mm., is as follows: Head 
3.7 to 4.1; depth 5 to 6; D. 8 or 9; A. 12 or 13; scales 33 to 38, com- 
plete longitudinal rows between bases of dorsal and anal 8 or 9. 
Snout 4 to 5.2 in head; eye 3.75 to 4.6; interorbital 2.8 to 3.4; width 
of head 1.4 to 1.6; depth of head 1.7 to 2.3; caudal peduncle 1.9 to 
2.2 in head, or 7.6 to 8.6 in standard length; pectoral 1.4 to 1.7 
in head. 

The single adult female at hand, 44 mm. long, has a dark ocellus 
at the base of the upper rays of the caudal. It is rather lighter in 
color than the adult males, and in contrast with the males it has dark 
markings on the anterior part of the body, which tend to form lines 
along the rows of scales; posteriorly, contrary to the males, dark 
spots are missing, except for a few at the base of the caudal. The 
dorsal bears black spots as in the male, but the caudal is plain dusky, 
and the anal is very pale at the base, becoming dusky along the 
margin. The ventrals are pale, and the pectorals are only slightly 
dusky. Immature fish are all more or less speckled with dark 
specks; lower part of caudal with or without a black longitudinal 
stripe, forming an intramarginal band. 

The dorsal and anal fins are not quite as high in the adult female 
as in large males, though similar in shape, and the caudal fin is 
about equally pointed. 

The immature specimens, 26 to 38 mm. long, from a small stream 
on the Atlantic slope near the summit of the ridge, at Culebra, 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 321 

Canal Zone, collected in 1911, and listed as R. elegans by us (1916, 
p. 331) were re-examined, and appear to belong to the present species. 
This species differs from R. elegans, following the original descrip- 
tion and figure (Steindachner, 1880; p. 33, fig. 6) (a) in the pointed 
caudal fin, which is shown as somewhat concave in Steindachner's 
figure of elegans, though described as broadly rounded to square; (6) 
in the apparently fewer anal rays, that is, 11 or 12 in the present 
species, and 13 to 15 in elegans; (c) in the fewer scales on the base of 
the caudal, present only on the basal third of the fin, whereas in 
elegans they cover the basal half; (d) the pectoral fins are shorter 
as they reach within half an eye's diameter of the base of the ventrals 
in elegans, whereas the space between these fins in the adults of the 
present species exceeds the full diameter of the eye; and () in color, 
the species differing principally in the color of the spots on the body, 
which are dark or black in the present species, whereas they are 






FIG. 9. Rivulus montium sp. nov. Type, male, 66 mm. long. (From drawing 
by Andrew Pizzini.) 

indicated in Steindachner's figure as pale, and most distinct on the 
third and fourth row of scales below the base of the dorsal. The 
anal fin in males is distinctly spotted with black in the present species. 
No spots are shown on this fin in Steindachner's figure, which is 
presumably based on a male, as no caudal ocellus is shown. 

This species apparently lives in small mountain streams, and to 
date is known only from the Chagres Basin from the type and six 
paratypes taken in a mountain trickle on the ridge between the 
Rio Pequeni and the Rio Boqueron (upper tributaries of the Chagres) 
by J. A. Griswold, and from 22 immature specimens taken in very 
small streams on the Atlantic slope near the summit at Culebra by 
us in 1911. The specimens taken by Mr. Griswold were sent to the 
Museum of Comparative Zoology for identification, and were lent 
for study through the kindness of W. C. Schroeder, curator of fishes 
in that museum. The type has been deposited in the Museum of 
Comparative Zoology, as already shown, but some of the paratypes 





322 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

wall be retained, with the permission of Mr. Schroeder, for the 
National Museum. 

As this species has been taken only in the mountains it is here 
named montium. 

Family MUGILIDAE. Mullets; Liza; Dajao 
Agonostomus Bennett. 

The fresh-water mullets of this genus are known quite generally 
as "dajao" in Central America and the West Indies. They resemble 
the marine mullets in many respects, but differ in having a normal 
stomach, not gizzard-like as in the marine forms. The walls in 
Agonostomus, nevertheless, are rather thick. The mouth is larger, 
with heavier lips, the cleft extending laterally to or beyond the front 
of the eye, and the lower jaw is rounded (not angulate) anteriorly. 
The anal fin has only two spines that are free distally. However, a 
third, undivided ray is attached to the first divided or articulated 
ray. The young of the marine mullets have the third ray similarly 
constructed shortly before it becomes a definite spine with a sharp 
point. In Agonostomus the third ray apparently never becomes a 
definite spine. The anal formulae, as generally written, therefore, 
show only two spines, the third ray being included with the ones 
divided. 

Two species which may prove to intergrade, namely, monticola 
and macr acanthus, are recorded from Panama. A. macracanthus 
is apparently rare and differs from the more common one only in 
having a somewhat deeper body and a larger mouth. 

Agonostomus monticola (Bancroft). 

Mugil monticola Bancroft, in Griffith's Edition of Cuvier's Animal Kingdom, 

Fishes, p. 367, pi. 36, 1836 West Indies. 
Agonostomus monlicola Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 334, 1916. 

This species was taken in 1935 and 1937 at Fort Sherman (Toro 
Point), and in the Rio Cocoli, a tributary of Miraflores Lake, Canal 
Zone. It is evident, therefore, that the species occurs in both the 
Atlantic and Pacific drainages, which it also did before the opening 
of the Canal. As the species is apparently confined to rocky streams 
it probably seldom if ever enters the Canal. 

Dajao unmistakably were seen, but not captured, also in the 
Rio Capira at Campana, and in the Rio Chiriqui Viejo, at an eleva- 
tion of about 4,600 feet. The Rio Chiriqui Viejo, being rather far 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 323 

removed (in western Panama) from the other points where we col- 
lected, it seemed especially desirable to obtain samples there for 
comparison with the ones from central Panama, but all efforts failed. 
Behre (1928, p. 312), whose specimens I have not seen, recorded this 
species from both slopes of western Panama without comment, in- 
dicating that she considered her specimens true monticola. During 
the earlier investigations (1911 and 1912) this species was taken in 
the Chagres Basin, in small streams at Porto Bello, and Toro Point, 
and on the Pacific side in almost every stream sampled in central 
Panama. 

Dajao commonly inhabit rocky streams where seining is difficult, 
and they are as elusive as their salt-water relatives. They rarely 
take a hook. The species are valued as food, and reach a length of 
about 300 mm. 

This fish occurs from sea level to mountain streams. According 
to the contents of stomachs of specimens taken in Puerto Rico it 
feeds on rather small organisms, such as insects, insect larvae, 
sponges, and apparently on algae. A specimen taken at Toro Point 
had ingested a small grasshopper. 

This species is characterized by the rather slender, somewhat 
compressed body, which varies considerably in depth, being con- 
tained 3.2 to 4.1 in standard length; head 3 to 4.1; D. IV-I, 8; A. II 
(or III) 8 to 10; scales 38 to 43. The mouth is rather small, the 
maxillary reaching only to or a little beyond the anterior margin of 
the eye, 2.6 to 3.2 in head; eye 3.3 to 4.9; snout 3.1 to 4.3. The 
color is bluish black above, pale below, and in life yellowish along 
the sides, the brightness varying according to place of capture, 
those living in clear upland streams generally being more highly 
colored. The young sometimes have a dark lateral band, at least 
posteriorly, and a dark caudal spot seems to be present at all ages. 

This species is recorded from Mexico, Central America, and the 
West Indies. Although it is common on both slopes of central 
Panama it has not been reported from eastern Panama, nor from 
Colombia. 

Agonostomus macracanthus Regan. 

Agonostomus macracanthus Regan, Ann.Mag. Nat. Hist., (7), 19, p. 65, 1907 
Rio Guacalate, Guatemala; Meek and Hildebrand, Field Mus. Nat. 
Hist., Zool. Ser., 10, p. 335, 1916. 

No specimens of this apparently rare species were secured in 
1935 and 1937. We reported in our earlier work only two specimens, 
which were taken in the Rio Indio, an upper tributary of the Chagres. 



324 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Behre (1928, p. 312) recorded four specimens from the Atlantic slope 
of extreme western Panama. It is not reported from eastern Panama, 
though Eigenmann (1922, p. 187) recorded two specimens from San 
Lorenzo, Colombia. 

Its range, according to the literature at hand, extends from the 
Rio Guacalate (Pacific), Guatemala to San Lorenzo (Atlantic), 
Colombia. 

Joturus pichardi Poey. 

Joturus pichardi Poey, Memorias, 2, p. 263, 1860 Cascades throughout 
Cuba; Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 336, 
1916. 

This fish is known from Panama only from the Chagres Basin. 
It lives at the base of waterfalls. It was not taken in 1935 nor 1937. 
The specimens reported by us (1916, p. 336) were caught at the foot 
of waterfalls on the Rio Indio, an upper tributary of the Chagres, 
and at the base of the Gatun "Spillway," an artificial falls. 

This species is known from Cuba, and from Mexico to Panama. 

Family CICHLIDAE. Mojarras 

Five genera were included in our earlier (1916) work. One genus, 
Herotilapia (with one species) is now added on the basis of a record 
by Behre (1928) from western Panama. This genus is readily 
recognized by the compressed, incisor-like, tricuspid teeth. Its nearest 
relative in central Panama is Neetroplus, which has simple incisors 
in the jaws; that is, compressed teeth with even cutting edges. 

Six species of the genus Cichlasoma were added to the fauna of 
Panama by Dr. Behre, in the paper already referred to, since the 
publication of our earlier work. Dr. Behre collected in extreme 
western Panama, which appears to be inhabited chiefly by Central 
American species. The specimens collected by Dr. Behre were not 
seen by me. 

The common name for this family usually appearing in books is 
"mojarras." However, ichthyologists use the name "cichlids," de- 
rived from the generic name Cichlasoma. This term appears several 
times in the following pages. 

Aequidens coeruleopunctatus (Kner and Steindachner). 
"CHOGORRO." 

Acara coeruleopunctata Kner and Steindachner, Sitzber. Akad. Wiss., Mtinchen, 

p. 222, 1863 Rio Chagres, Isthmus of Panama. 
Aequidens coeruleopunctata Meek and Hildebrand, Field Mus. Nat. Hist., 

Zool. Ser., 10, p. 339, 1916. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 325 

This is one of the most generally distributed species in the waters 
of central and eastern Panama. Specimens were taken on the 
Atlantic side, in 1935 and 1937, in a creek below an abandoned 
reservoir at Gatun; in Gatun Lake at Gatun, Barro Colorado Island, 
and several places between Gamboa and Madden Dam; and in a 
creek tributary to Gatun Lake on Madden Dam Road. On the 
Pacific side it was secured in coastal streams between Campana and 
La Venta, Rio Capira at Campana, Rio Pacora on the Chepo Road, 
La Jagua Hunting Club, Miraflores Lake, and in the Rio Cocoli. 
It was not present in the locks at either end of the Canal when they 
were dewatered in 1935 and 1937. 

This species does not grow large enough to have much value as 
a food fish. The largest specimen at hand is only 145 mm. long, 
though one of 157 mm. has been reported. The average size is only 
about 100 mm. It is not as numerous in Gatun and Miraflores 
lakes as Cichlasoma maculicauda. 

Breder (1927, p. 139) has reported that this fish, according to 
stomachs examined by him, feeds largely on insects, though a large 
amount of debris, including some plant tissue, was present. The 
three stomachs examined by me all contained fragments of insects. 
One contained a mass of crushed molluscan shells; two contained a few 
ostracods; and one definitely contained fragments of a plant. The 
pharyngeal teeth are well developed, in two large patches above 
and one below, and the individual teeth are rather blunt. The 
presence of this grinding apparatus, together with the fragmentary 
appearance of the foods ingested, suggests that a fair degree of 
mastication precedes swallowing. 

This cichlid is easy to recognize in life, among its relatives in 
Panama, by the emerald green spots on the head and sides, and by 
two lines of the same color on the cheeks. These spots and lines 
generally remain visible in preserved specimens but become dusky. 
A more or less definite dark lateral band is generally present, with 
an intensely black blotch below the spinous dorsal, and frequently 
with a second but smaller black spot at the base of the caudal. 
The young lack the emerald green spots and lines mentioned, and 
are distinctly barred with black. These black bars often persist in 
adults and form saddle-like blotches on the back. The gill arches 
are normally formed, and the gill rakers are short and fleshy, more 
or less fan-shaped, and only seven or eight are more or less developed 
on the lower limb of the first arch. In adults the head is broad, and 
the interorbital greatly exceeds the diameter of the eye. The anal 



326 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

fin consists of only 3 spines and 7 or 8 soft rays, and the dorsal has 
14 or 15 spines and 9 to 11 soft rays. The scales are large, as there 
are only 26 or 27 in a lateral series and only 3 between the lateral 
line and the origin of the dorsal. The body is not as deep as in some 
of the other cichlids, as the depth is contained 2 to 2.3 times in the 
standard length. 

Two of three specimens dissected were females with large roe. 
One of these was taken February 11 and the other April 2. The 
third specimen, a male, caught February 23, was undeveloped. 
Many young, ranging upward of 10 mm., apparently belonging to 
this species, were collected during February. The indications, 
therefore, are that spawning takes place during the dry season. 

The range extends from central (both slopes) to eastern Panama 
and somewhat doubtfully into Colombia and northwestern Ecuador. 
In Colombia it seems to be replaced chiefly by A. latifrons, which 
from a study of descriptions (no specimens being available) seems 
doubtfully distinct. A. coeruleopunctatus has not been recorded 
from western Panama. 

Geophagus crassilabris Steindachner. 

Geophagus crassilabris Steindachner, Sitzber. Akad. Wiss., Wien, 74, p. 65, 
pi. 7, 1876 vicinity of Candelaria, Isthmus of Panama; Meek and Hilde- 
brand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 340, 1916. 

This cichlid is rather common in the streams of both slopes of 
central Panama, and also in the Tuyra Basin, as shown by col- 
lections made by us in 1911 and 1912 and by Breder (1927, p. 139). 
In 1935 and 1937 it was taken only in Gatun Lake near Madden 
Dam, in a creek tributary to Gatun Lake on the Madden Dam 
Road, and in Miraflores Lake. This species is known to reach a 
length of at least 265 mm. Although it was taken in both Gatun 
and Miraflores lakes, it does not seem to be common, and probably 
cannot be considered available as a food and game fish. 

This species is readily recognized by its long, pointed snout, 
which is much longer than the postorbital part of the head in adults, 
and proportionately much longer than in any other cichlid known 
from Panama. It differs from all other Panama species, further- 
more, in the peculiar development of the upper part of the gill arch, 
which is provided with a fleshy growth, usually described as a lamelli- 
form lobe. Adult males have a very prominent nuchal hump. This 
species has only 3 anal spines and 7 or 8 soft rays. Its dorsal fin 
consists of 16 spines and 9 or 10 soft rays. Most specimens have 
more or less definite crossbars, and the young also have a black 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 327 

lateral band. A fresh specimen, about 175 mm. long, had the color 
as follows: Greenish above, slightly golden on the belly, with indi- 
cations of dark broken crossbars on the sides, and a large black 
blotch on the side below the posterior part of the spinous dorsal. 
The large lips were dark blue, and the opercle bluish green to black. 
Individual scales on the side were bluish green. The pectorals were 
greenish, and all the other fins were pink to reddish. 

The range seems to be limited to both slopes of central and 
eastern Panama. It has not been taken in western Panama. In 
Colombia it seems to be replaced by the closely related G. pellegrini. 

Cichlasoma Swainson. 

All the cichlids known to occur in Panama having conical, or 
somewhat compressed teeth, yet surmounted by conical apices (not 
incisor-like teeth), in combination with 5 or more anal spines, are 
herein included in the genus Cichlasoma. It seems advisable to 
present a key, because six species not included in our earlier pub- 
lication (1916) have been added by the work of Behre (1928). 
Unfortunately, it has not been possible to examine Dr. Behre's 
collection, and no other specimens have been available to me for 
examination of altifrons or lethrinus. Therefore, it has been neces- 
sary to rely partly on published accounts for some of the characters 
used in the key. 

KEY TO SPECIES OF CICHLASOMA 

a. Teeth all conical or pointed, not notably or at all compressed; fold of lower lip 

continuous or interrupted. 

b. Snout long, much longer than postorbital part of head; D. XVI, 11; A. V, 
8 or 9; about 30 scales in lateral series; body with 5 or 6 dark crossbars; 

no lateral band altifrons. 

bb. Snout shorter, little if any longer than postorbital part of head; dorsal 

usually with 17 or 18 spines; anal with 6 to 10 spines, 
c. Lower lip broad, with a continuous free fold; body moderately to quite 

elongate, the depth about 2.2 to 3 in standard length. 
d. Body quite elongate and robust, the depth about 2.5 to 3 in standard 
length; lower jaw projecting; anterior pair of teeth in upper jaw 
notably enlarged, canine-like; sides with a series of dark spots 
forming a more or less continuous lateral band; definite dark bars 
present only in young; D. XVII or XVIII, 10 or 12; A. VII, 8 to 10; 
scales 30 to 32, 5 or 6 rows between lateral line and origin of dorsal, 
but only 3 between lateral line and middle of base of dorsal. 

motaguense. 

dd. Body rather deeper and more strongly compressed, the depth about 

2.15 to 2.5 in standard length; lower jaw not reaching beyond the 

upper one; none of the teeth greatly enlarged or canine-like. 

e. Snout long and rather pointed, equal to or somewhat longer than 

postorbital part of head; lateral line rather strongly arched, only 

3 or 4 complete rows of scales between it and origin as well as 

middle of dorsal; sides with a large black blotch under middle of 



328 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

base of dorsal, a smaller one on upper half of base of caudal; 
distinct crossbars and a lateral band present only in young. 

calobrense. 

ee. Snout shorter, less pointed, a little shorter than postorbital part of 
head; lateral line less strongly arched, with 5 or 6 complete rows 
of scales between it and the origin as well as middle of dorsal; 
sides with a rather narrow, well-defined, continuous black lateral 

band; no crossbars except in very young umbriferum. 

cc. Lower lip narrower, the fold not continuous, being interrupted anteriorly; 

body deep to only moderately elongate. 
/. Body very deep, the depth 1.75 to 2 in standard length. 

g. Scales rather small, 34 to 40 in lateral series; lateral line at point of 
interruption reappearing on fifth row of scales below its original 
course; adults with a series of about six dark blotches along 
middle of side; young with dark crossbars; scales with dark dots, 

forming more or less definite rows tuyrense. 

gg. Scales larger, 28 to 33 in lateral series; lateral line at point of inter- 
ruption reappearing on third row of scales below its original 
course. 

h. Scales large, 28 to 30 in lateral series, 2 or 3 complete rows between 
lateral line and middle of base of dorsal; D. XVIII or XIX, 
9 or 10; A. VIII or IX, 7 or 8; sides with about 7 crossbars; 

no lateral band spilurum. 

hh. Scales somewhat smaller, 31 to 33 in a lateral series, 5 or 6 complete 
rows between lateral line and middle of dorsal; D. XVII or 
XVIII, 11 or 12; A. VI, 9 or 10; no distinct bars and no lateral 
band, except in very young; a large black blotch at base of 

caudal maculicauda. 

//. Body moderately elongate, the depth about 2.3 to 2.6 in standard length. 

t. Scales large, 29 to 31 in lateral series; D. XVII or XVIII, 10 to 12; 

pectoral nearly as long as head, reaching to first or second anal 

spine; sides with 6 dark crossbars, and a more or less continuous 

dark lateral band; sides of head not spotted lethrinus. 

ii. Scales slightly smaller, 31 to 34 in lateral series; D. XVI to XVIII, 

12 to 14; pectoral only about three-fourths length of head, not 

extending to origin of anal; sides often without bars, sometimes 

with blotches along lateral line; sides of head spotted . . gutiulatum. 

aa. Teeth more or less flattened, but with conical apices; fold of lower lip not 

continuous, being interrupted anteriorly. 

?". Sides with about 9 dark crossbars, the first two bent forward across nape; no 
dark spots on scales; D. XVII to XIX, 8 or 9; A. VIII to X, 5 to 8; scales 

27 to 30 nigrofasciatum. 

jj. Sides with 5 or 6 more or less interrupted bars, forming a series of blotches 
above lateral line, and another series at or somewhat below middle of 
side; no bars on nape; scales and vertical fins with dark spots; D. XVII, 
11; A. V, 8; scales 30 to 32 sieboldii. 

Cichlasoma altifrons (Kner and Steindachner). 

Heros altifrons Kner and Steindachner, Abhandl. Bayer. Akad. Wiss., Mun- 
chen, 10, p. 11, pi. 2, fig. 1, 1864 "New Granada." 

This species was omitted from our earlier publication because of 
the uncertainty regarding the type locality. It is now included in 
the fauna of Panama, principally because specimens have been 
recorded from the Atlantic slope of extreme western Panama by 
Behre (1928, p. 321). 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 329 

The type locality given for this species by Kner and Steindachner 
is "New Granada," or Colombia. However, Eigenmann (1922) did 
not record it from Colombia, and it has not been taken in eastern 
or central Panama by us or, according to the records available, by 
other collectors. If I interpret Gunther (1868, p. 459) correctly, 
he indicated without qualification that the types came from Chiri- 
quf , Pacific slope of western Panama. Regan (1908, p. 463) recorded 
it from the Rio Grande de TeYraba (Pacific slope), Costa Rica. 
Meek (1914) did not take this species in Costa Rica, and it was not 
included in a collection from that country made by Dr. Anastasio 
Alfaro, reported upon by me (1930). The species may be rather 
rare and the distribution peculiar. According to the records, as 
already shown, the species occurs in Colombia, both slopes of 
western Panama and the Pacific slope of Costa Rica. 

Head about 2.75; depth 2.3; D. XVI, 11; A.V, 8 or 9; scales 
31 to 33. 

Snout notably longer than postorbital part of head; eye 4 to 5 
in head; mouth rather small, nearly terminal; maxillary not reaching 
eye; lips thick, the fold of the lower one split anteriorly; teeth 
conical, the outer and anterior ones scarcely enlarged; cheeks with 
4 or 5 series of scales; dorsal spines graduated, the last one scarcely 
half the length of head; caudal rounded to more or less truncate; 
pectoral scarcely reaching origin of anal. 

Color brownish; sides with 4 or 5 dark bars; body, and vertical 
fins exclusive of spinous parts, spotted (condensed after Kner and 
Steindachner). 

Cichlasoma motaguense (Gunther). 

Heros motaguense Gunther, Trans. Zool. Soc. Lond., 6, p. 462, pi. 77, fig. 3, 
1868 Rio Motagua, Guatemala. 

This cichlid is included in the Panama fauna on the basis of 
specimens recorded by Behre (1928, p. 320), collected in the Atlantic 
drainage of extreme western Panama. 

Head 2.35 to 2.8; depth 2.2 to 3; D. XVII to XIX, 10 to 12; 
A. VII or VIII, 8 to 10; scales 30 to 32. 

Body rather elongate and robust; caudal peduncle short; its 
depth 2.55 to 3 in head; snout nearly as long as postorbital part of 
head, 2.4 to 2.7; eye 3.25 to 6.1; mouth moderately large, oblique, 
lower jaw projecting, maxillary nearly reaching eye; lower lip with 
an uninterrupted fold; teeth conical, the anterior pair in upper jaw 
enlarged, canine-like; 5 or 6 rows of scales between lateral line and 



330 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

origin of dorsal; about 8 series on cheek; dorsal spines graduated, 
the last one scarcely a third the length of head, caudal broadly 
rounded; pectoral fins reaching scarcely to tip of ventrals and not 
quite to origin of anal, 1.5 to 1.7 in head. 

Color dark green to bluish above, more or less silvery underneath. 
Sides with dark blotches, forming an interrupted lateral band. 
Young with crossbars and a more pronounced lateral band. Body 
and head, except snout, with rusty spots, which are present also on 
the vertical fins (described from specimens collected in El Salvador). 

The range apparently extends from British Honduras (Belize), 
the Rio Motagua, Guatemala, to the Atlantic slope of western 
Panama, though it does not seem to have been recorded from inter- 
mediate localities. On the Pacific slope it has been recorded from 
several lakes in El Salvador (including Lake Guija, which is partly 
in Guatemala). 

Cichlasoma calobrense Meek and Hildebrand. 

Cichlasoma calobrense Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 90, 1913 Rio Calobre, Panama; p. 346, pi. 29, 1916. 

This cichlid is recorded from the Bayano and Tuyra basins in 
our earlier work (1916, p. 346), the type being from the Rio Calobre, 
a tributary of the Bayano. Breder (1927, p. 140) reported it from 
the Chucunaque Basin from near Yavisa. Although the species 
has not been taken in the vicinity of the Canal Zone, and never 
before in the Atlantic drainage, Behre (1928, p. 322) recorded it 
from the Atlantic slope on both sides of the Panama-Costa Rica 
border. 

Cichlasoma umbriferum Meek and Hildebrand. 

Cichlasoma umbriferum Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 88, 1913 Rio Cupe, Cituro, Panama; p. 347, pi. 30, 1916. 

This species was reported from the Rio Tuyra by us (1916, p. 
347), the type being from the Rio Cupe, one of the larger tributaries. 
Breder (1927, p. 140) found it common in the Rio Sucubti, an upper 
tributary of the Rio Chucunaque, where he took specimens up to 
340 mm. in length, which are much larger than any seen by us. 

Eigenmann (1922, p. 207) reported this cichlid from the "Chepo, 
Tuyra, Atrato, and Magdalena basins." We have no record of its 
occurrence in the Chepo River and believe that "Chepo" was 
included by mistake. Therefore, its habitat, so far as known to 
date, is restricted to the Tuyra, Atrato, and Magdalena basins. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 331 

Cichlasoma tuyrense Meek and Hildebrand. 

Cichlasoma tuyrense Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 89, 1913 Rio Tuyra, Boca de Cupe, Panama; p. 344, pi. 28, 1916. 

This species, reported from the Bayano and Tuyra basins in our 
earlier work (1916, p. 344), has since been reported (Breder, 1927, p. 
140) , also from the Rio Chucunaque, a large tributary of the Tuyra not 
visited by us. It is not reported from the Canal Zone and westward. 

Cichlasoma spilurum (Giinther). 

Heros spilurus Giinther, Cat. Fish. Brit. Mus., 4, p. 289, 1862 Lake Yzabal, 
Guatemala. 

This fish is included here because of a record by Behre (1928, 
p. 321), who took it in the Atlantic drainage of extreme western 
Panama. Dr. Behre remarked: "This species has hitherto been 
described no farther south than the Atlantic slope of Guatemala, La 
Yzabal and Rio Motagua, except in the Canal Zone. It is strange 
that we should have found no examples from any except the southern 
limit of our territory. The only Canal Zone specimen available for 
comparison has been injured anteriorly so seriously as to invalidate 
measurements." I know of no Canal Zone record, other than this 
one by Dr. Behre, and have never taken a specimen there. If Dr. 
Behre's record is based solely on the injured specimen mentioned it 
may be that the identification is not reliable. In making the remarks 
quoted, Dr. Behre apparently overlooked the records by Meek (1914, 
p. 126) who took this species in Costa Rica in both the Atlantic and 
Pacific drainages. 

Head 3; depth 2; D. XVIII or XIX, 9 or 10; A. VIII to X, 7 or 8; 
scales 28 to 30. 

Snout as long as or somewhat longer than postorbital part of 
head, eye 3 to 4 times in head; mouth very small, terminal, the 
maxillary not nearly reaching the eye; fold of lower lip interrupted 
anteriorly; teeth in jaws pointed, the outer ones somewhat enlarged; 
2 to 23^ rows of scales between lateral line and beginning of soft 
dorsal, 4 or 5 series on cheek; last dorsal spine 1.8 to 2 in head; 
caudal rounded or subtruncate; pectoral as long as or longer than 
head, reaching third to fifth anal spine, 1.15 in head. 

Color olive green with 7 to 9 dark vertical bars; a large black 
spot or vertical bar at base of caudal ; vertical fins dusky, sometimes 
spotted. Although the description was compiled from published 
accounts, the characters were checked from specimens in the United 
States National Museum, collected in Guatemala. 

The range probably extends from Guatemala to western Panama. 



332 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Cichlasoma maculicauda Regan. "CHOGORRO." 

Cichlasoma maculicauda Regan, Ann. Mag. Nat. Hist., (7), 16, p. 227, 1905 
Lake Yzabal and Rio Motagua, Guatemala, Rio Chagres, Panama; Meek 
and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, p. 343, 1916. 

Heretofore this species has been recorded in Panama only from 
the lower part of the Chagres Basin. In 1935 and 1937 it was taken 
on the Pacific side of the divide on the Canal Zone, namely, in Pedro 
Miguel Locks, Miraflores Lake, and in the upper chamber of Mira- 
flores Locks. These places it apparently has reached by migrating 
through Culebra Cut. On the Atlantic side it was secured in Gatun 
Lake at Barro Colorado Island, at several places between Gamboa 
and Madden Dam; and also in the uppermost chamber of Gatun 
Locks. This fish seems to be fairly common both in Gatun and 
Miraflores lakes, as numerous specimens were taken. 

This cichlid resembles the bluegill sunfish (Lepomis incisor}, in 
the general shape of the body, in size, and somewhat in color. It is 
believed, therefore, that those few American residents of the Canal 
Zone who have reported the successful introduction of the bluegill 
sunfish (planted in Gatun Lake two or three different times, some 
years ago) have mistaken this cichlid for that sunfish, which appar- 
ently failed to become established. Its qualities as a food fish were 
not sampled by me, though an American at Pedro Miguel, who 
believed the fish to be the bluegill, said it was a good pan fish. 

I could learn nothing of the game qualities of this cichlid from 
the local residents, and did not take the time to learn something 
about them at first hand. The fish, no doubt, is chiefly carnivorous, 
as shown by its teeth, the short alimentary canal, and the contents 
of the five stomachs examined. The principal food appears to con- 
sist of small mollusks. One specimen contained a great mass of 
debris, which apparently was in part plant tissue. Its prominent 
pharyngeal teeth are apparently well adapted to crushing shells. As 
this fish has a small mouth, small hooks would be necessary, and the 
bait apparently should consist of a small animal or of meat. Since 
the fish appears to be a bottom feeder, it should be fished for at or 
near the bottom. Because of its abundance, this species, if it can be 
induced to take the hook, apparently would be the most promising 
as a game fish of any indigenous species in the artificial lakes of the 
Canal. It grows sufficiently large to have value as a food fish, as 
many examples ranging from 250 to 320 mm. in length were taken. 

This fish is readily recognized among Panama species by the 
deep body, the depth being contained in the standard length about 



1938 FRESH-WATER FISHES OF PANAMA HILDEBRAND 333 

1.8 to 2.1 times; by the large scales, there being only 31 to 33 in a 
lateral series; and by the large black blotch on the peduncle at the 
base of the caudal. Frequently a second black blotch appears on 
the side below the posterior half of the spinous part of the dorsal. 
Very young have a dark lateral band, but distinct dark bars are 
wanting. The dorsal is composed of 17 (sometimes 16 or 18) spines 
and 11 to 13 soft rays; and the anal of 6 spines and 9 (sometimes 
8 or 10) soft rays. 

Five fish, taken in February, were dissected. One female con- 
tained large roe, indicating that spawning probably takes place 
during the dry season. Males do not develop a very prominent 
nuchal hump, as in some of the other species of this family. 

The natural range as now understood extends from British 
Honduras (Belize) to Panama on the Atlantic slope. The occurrence 
in Miraflores Lake, herein reported, apparently is the result of 
migration from the Atlantic to the Pacific slope through Culebra 
Cut. It is to be remarked that C. maculicauda was not contained in 
a rather large collection from Costa Rica, reported upon by Meek 
(1914); neither was it included in collections from that country 
studied by the writer (1930); and Behre (1928), who collected exten- 
sively on the Atlantic slope of both sides of the Panama-Costa Rica 
border, failed to get it. It is strange, therefore, that this species is 
unreported, except for a record by Fowler (1916, p. 399), without 
comment, from Port Limon, Costa Rica, in the territory between 
the Canal Zone and the Motagua Basin, Guatemala. It is possible 
that upon comparison of specimens from the Chagres and the 
Motagua basins, which is not possible for me at this time, it may 
be found that the fish from the two river systems are not identical, 
though no differences are evident from published descriptions. 

Cichlasoma lethrinus Regan. 

Cichlasoma lethrinus Regan, Ann. Mag. Nat. Hist., (8), 2, p. 462, 1908 
Rio Iroquois, Costa Rica. 

This species was taken by Behre (1928, p. 322) in streams of the 
Atlantic drainage on both sides of the Panama-Costa Rica border. 
It has been recorded from both slopes of Costa Rica (Meek, 1914, 
p. 126). 

Head 2.66 to 3; depth 2.33; D. XVII or XVIII, 10 to 12; A. VI 
or VII, 8 to 10; scales 29 to 31. 

Snout equal to or a little longer than postorbital part of head; 
eye 3.5 to 4.5 in head; mouth terminal; maxillary not extending to 
eye; fold of lower lip interrupted anteriorly; teeth in outer series in 



334 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

both jaws somewhat enlarged anteriorly, gradually decreasing in size 
laterally; 2^ rows of scales between lateral line and beginning of soft 
part of dorsal, 4 to 43^ at origin of dorsal, 5 series on cheek; dorsal 
spines subequal from fifth to fifteenth, the last about 3 in head; caudal 
rounded; pectoral not much shorter than head, extending to above 
first or second anal spine. 

Body with 6 dark crossbars, the first two broad and more or less 
confluent; a more or less continuous blackish longitudinal band from 
the eye to a spot on the upper part of the base of the caudal; vertical 
fins dusky, the soft dorsal and caudal with series of pale spots (con- 
densed after Regan's original description). 

Known from both slopes of Costa Rica and from the Atlantic 
slope of extreme western Panama. 

Cichlasoma guttulatum (Giinther). 

Heros guttulatus Gimther, Proc. Zool. Soc. Lond., 1864, p. 152; Trans. Zool. 
Soc. Lond., 6, p. 466, pi. 78, fig. 3, 1868 Lake Amatitlan, Guatemala. 

This species, as well as several other cichlids, is included here 
in the fauna of Panama on the basis of specimens reported from the 
Atlantic slope of extreme western Panama by Behre (1928, p. 321). 
So far as I am aware it has not been reported from localities between 
Lake Amatitlan, Guatemala, and the Atlantic slope of far western 
Panama. 

Head 2.8 to 3.4; depth 2.25 to 2.6; D. XVI to XVIII, 12 to 14; 
A. VI or VII, 9 or 10; scales 31 to 34. 

Snout nearly as long as, or in large examples somewhat longer 
than, postorbital part of head; eye 3 to 4.65 in head; mouth rather 
small, nearly terminal; maxillary not reaching eye; fold of lower lip 
interrupted anteriorly; teeth conical, the anterior ones somewhat 
enlarged; 5 series of scales on cheek, 3^ to 4^ between lateral line 
and beginning of soft part of dorsal; the last dorsal spine about 4 in 
head; caudal sub truncate or rounded; pectoral not reaching origin 
of anal, 1.33 in head. 

Color brownish; a broad dark band extending from above 
pectoral to base of caudal, this band sometimes interrupted, forming 
blotches; some specimens with 5 or 6 crossbars; sides of head and 
body, as well as the vertical fins, often spotted. (Though the 
description was compiled from published accounts, the characters 
were checked from specimens in the National Museum, taken in 
Lake Amatitlan, Guatemala.) 

The range apparently extends from southern Mexico (Rio de 
Sarabia) to the Atlantic slope of extreme western Panama. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 335 
Cichlasoma nigrofasciatum (Giinther). 

Heros nigrofasciatus Giinther, Trans. Zool. Soc. Lond., 6, p. 452, pi. 74, fag. 3, 
1868 lakes Atitlan and Amatitlan. 

This species was recorded from the Atlantic drainage from both 
sides of the Panama-Costa Rica border by Behre (1928, p. 323). It 
has been reported also from lakes Atitlan and Amatitlan (type 
localities) in Guatemala, from several lakes and streams in El 
Salvador, and from some rivers of the Pacific slope of Costa Rica. 

Head 2.55 to 3.35; depth 1.9 to 2.25; D. XVII to XIX, 8 or 9; 
A. VIII to X, 5 to 8; scales 27 to 30; vertebrae 13+15. 

Body compressed, short and deep; caudal peduncle short and 
deep, its depth 1.7 to 2.5 in head; snout shorter than postorbital 
part of head, 2.4 to 3.3 in head; eye 3.2 to 4.6; mouth small, terminal; 
maxillary failing to reach eye, 3.25 to 4.15 in head; fold of lower lip 
interrupted anteriorly; outer series of teeth in jaws somewhat en- 
larged and compressed, but with conical apices; 4 or 5 rows of scales 
on cheek, 4 complete rows between lateral line and origin of dorsal ; 
dorsal spines graduated, the last one equal to postorbital part of 
head; caudal fin broadly rounded; pectoral reaching to or beyond 
origin of anal, 1.05 to 1.4 in head. 

Color grayish green above, pale pinkish with silvery reflections 
below. Sides with 9 black bars, the first and second bent forward 
across nape, the second often meeting the third one on middle of 
side to form a V. Fins all dusky to black (description based on 
specimens from El Salvador and the Pacific slope of Costa Rica). 

This species has been placed by some authors under Paranee- 
troplus, a genus based principally on the shape of the outer teeth in 
the jaws, which are described as somewhat flattened, but with 
rounded and pointed apices. Others have questioned the validity 
of this character, because of variation in the shape of the teeth. 
That considerable variation in dentition may occur within one species 
was pointed out by Meek (1914, p. 124) and by the present writer 
(1930, p. 8). Because of these variations this species is placed in 
the genus Cichlasoma herein, as in our earlier work. 

This species ranges from lakes Atitlan and Amatitlan, Guate- 
mala, to the Atlantic slope of extreme western Panama. 

Cichlasoma sieboldii (Kner and Steindachner). 

Heros sieboldii Kner and Steindachner, Abhandl. Bayer. Akad. Wiss., 
Munchen, 10, p. 13, pi. 2, fig. 2, 1864 New Granada and the west slope 
of the Isthmus of Panama; Meek and Hildebrand, Field Mus. Nat. Hist., 
Zool. Ser., 10, p. 345, 1916. 



336 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

This species was included in our earlier publication (1916, p. 345), 
because the original describers gave as type localities "New Granada" 
and the "west slope of the Isthmus of Panama." No streams or 
definite localities were named as places of capture of the 11 specimens, 
125 to 200 mm. long, described. This cichlid was not reported from 
Colombia by Eigenmann (1922), and it apparently has not been seen 
in Panama since the record by Kner and Steindachner, unless the 
specimens reported under the name Paraneetroplus sieboldii by 
Behre (1928, p. 323) from the Rio Chiriqui del Tire (Pacific slope of 
western Panama) are the same. The identity is questioned by Dr. 
Behre, for she stated: "Our specimens are probably the same fish as 
P. sieboldii from Costa Rica, Regan, not C. sieboldii from Panama." 
It is not clear just what the writer had in mind. Regan (1907, p. 30) 
described Herichthys underwoodi from Costa Rica, which he later in 
the same publication (p. 186) synonymized with H. sieboldii Kner and 
Steindacher. If Dr. Behre meant to say that Regan's sieboldii from 
Costa Rica is different from Heros sieboldii Kner and Steindachner, 
then her specimens should stand as C, underwoodi (Regan). Meek 
(1914, p. 127), in fact, so recognized his specimens from Costa Rica. 

I have examined a specimen in the National Museum (No. 102273) 
from the Quebrada de India, one of the tributaries of the Rio 
Goto (Pacific slope), Costa Rica, which agrees in seemingly all 
important characters with the description and figure of C. sieboldi 
(Kner and Steindachner). I am inclined therefore to follow Regan 
(1908, p. 186) in assuming that the Costa Rican material is identical 
with that described and figured by Kner and Steindachner. 

The following proportions and counts are based on the Costa 
Rica specimen examined, which is 130 mm. long (standard length 
102 mm.): Head 3; depth 2.5; D. XVII, 11; A. V, 8; scales 30. Snout 
scarcely longer than postorbital part of head, 2.25 in head; eye 4.25; 
interorbital 2.6; maxillary 3.8; caudal peduncle (depth) 2.25; longest 
dorsal spine 3.4; longest anal spine 2.8; pectoral 1.35. The outer 
teeth in both jaws are wide at the base, but the tips are pointed. 
The lateral line, at the point of interruption, begins again on the 
third row of scales below its original course. A slight indication of 
a dark lateral band is present; also a small caudal spot; on the upper 
half of the sides are dark blotches suggesting crossbars. The mem- 
branes of the dorsal and anal bear distinct black spots, which are 
indefinite on the caudal fin, and missing on the paired fins. 

If the types of C. sieboldii (Kner and Steindachner) actually were 
collected in New Granada and on the west slope of the Isthmus of 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 337 

Panama, it seems strange that this species was not taken there in 
the rather extensive collecting done in these regions since the be- 
ginning of the present century. 

This species, as already stated, is too imperfectly understood to 
state its range definitely. According to records it apparently occurs 
from Costa Rica to Colombia. 

Neetroplus panamensis Meek and Hildebrand. 

Neetroplus panamensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 90, 1913 Rio Mandingo, Bas Obispo, Canal Zone; p. 348, 
pi. 31, 1916. 

This species was taken by us in several places in the Chagres 
Basin in 1911 and 1912. During the recent investigation it was 
found only in a creek, tributary to Gatun Lake, on Madden Dam 
Road where 11 specimens ranging in length from 38 to 95 mm. were 
seined. To date no evidence has been found indicating that this 
fish has established itself in the artificial lakes of the Canal. It 
apparently does not grow large, as no specimen more than 103 mm. 
long has been recorded. 

This species differs from the others of the family known from 
Panama in having the anterior teeth in each jaw flattened, that is, 
more or less incisor-like, and with unindented cutting edges. The 
anal fin consists of 6, rarely 7, spines and 7 soft rays, and the dorsal 
has 17 or 18 spines and 9 or 10 soft rays. 

The young have rather definite dark crossbars. The one lying 
under about the twelfth and thirteenth spines is broadened toward 
the middle of the side and intensely black, and a black caudal spot 
is present. In adults the bars fade and sometimes disappear, but 
the black blotch on the side, and generally the caudal spot, remain. 
Frequently other dark blotches are present on the side in adults. 
The following remarks concerning color are based on a fresh speci- 
men 95 mm. long: General color dark olivaceous above, pinkish 
below. Many scales on sides with pearly spots, which are present 
also on the vertical fins. 

This species had been reported only from the Chagres Basin 
until Breder (1927, p. 140) reported it somewhat doubtfully from a 
single specimen, 82 mm. long, from the Rio Chucunaque, in eastern 
Panama. Mr. J. T. Nichols of the American Museum of Natural 
History has kindly sent me Mr. Breder's specimen for study. After 
comparing it with Chagres River specimens I am convinced that it 
is a true N. panamansis. The scale and fin-ray counts agree perfectly, 
and the proportions come well within the range of Chagres River 



338 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

specimens. Although the color markings on the sides of this speci- 
men, which is presumably a male, are not as distinct as in some males 
from the Chagres, they are similarly placed. In general, the dark 
color markings are less distinct in males than in females, but males 
have pale spots (probably pearly in life) on the soft dorsal and less 
distinctly on the caudal, which the females do not possess. These 
markings on the fins are rather more distinct on the Chucunaque 
specimen than on any Chagres River fish at hand. 

This species is known from the Chagres Basin, where it is com- 
mon, and from a single specimen from the Tuyra Basin. 

Herotilapia Pellegrin. 

This genus differs from Neetroplus only in having the compressed, 
incisor-like teeth tricuspid instead of having a continuous cutting 
edge. This genus is not included in our earlier (1916) work. 

Herotilapia multispinosa (Giinther). 

Heros multispinosus Giinther, Trans. Zool. Soc. Lond., 6, p. 453, pi. 74, 
fig. 2, 1868 Lake Managua, Nicaragua. 

This species is included in the Panama fauna on the basis of a 
record by Behre (1928, p. 324) who collected specimens (not seen by 
me) in the Atlantic drainage on both sides of the Panama-Costa 
Rica border. 

This cichlid is readily distinguished from other species in Panama 
by its tricuspid incisor-like teeth, a character recognized as of 
generic importance. The dorsal consists of 18 spines and 9 soft 
rays, and the anal of 11 spines and 7 or 8 soft rays. The scales are 
large, only 28 or 29 being present in a lateral series. The color is 
brownish olive, each scale being somewhat darkened at the base. 
A blackish lateral band extends from the eye to the base of the caudal, 
but is more or less broken posteriorly by dark blotches, indicative of 
bars, with a definite black blotch on the side below the posterior 
half of the spinous part of the dorsal. 

The range apparently extends from Nicaragua (Lake Managua) 
to the Atlantic slope of extreme western Panama, the species being 
recorded only from the type locality, Lake Managua, and from the 
Atlantic drainage from both sides of the Panama-Costa Rica border. 

Family GOBIIDAE. Gobies 

The family Gobiidae, as formerly understood, has been divided 
by some recent authors who recognized those forms that have the 
ventral fins separate, that is, not united to form a sucking disk, as 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 339 

a distinct family under the name Eleotridae. The present writer 
has no fault to find with this division, though he has found remark- 
able similarity in the appearance and development of the young. 
For convenience the species from the fresh waters of Panama are 
treated here as one family, as in the earlier work by Meek and Hilde- 
brand (1916). Only two genera, Awaous and Sicydium, with united 
ventrals are included. 

The fresh and brackish water gobies (Eleotridae) are more 
numerous as to species in Panama than elsewhere. Thirteen species 
with separate ventrals are recognized in the following pages. None 
is common to both slopes (except the few that have recently "crossed 
over" through the Canal), though five species of each slope have 
extremely close relatives on the opposite sides, leaving only two on 
the Atlantic and one on the Pacific slope without near relatives. 
Contrary to the other fresh-water families of Panama, this group 
seems to have its center of distribution on the Isthmus of Panama. 

Gobiomorus Lacpede. GUAVINA. 

Gobiomorus has replaced Philypnus, long used for this genus, on 
the basis of priority. 

Only two species of this genus, both occurring in Panama, are 
known. They are rather sluggish carnivorous fishes, generally 
occupying shallow weedy areas where they lie quietly, hiding more 
or less among the plants, from which they make quick excursions, if 
hunger prompts them, to seize almost any animal of suitable size 
that comes near. 

Although the species reach a sufficiently large size they do not 
seem to find much favor as food fishes. 

Gobiomorus dormitor Lace'pede. 

Gobiomorus dormitor Lacepede, Hist. Nat. Poiss., 2, p. 599, 1798 Martinique, 

from a drawing by Plumier. 
Philypnus dormitor Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 350, 1916. 

Thirty specimens of this species, ranging in length from 35 to 
185 mm., were preserved, and others were examined in the field. 
These specimens were collected at Cativa, and in Gatun Lake at 
Gatun, Barro Colorado Island, and a short distance below Madden 
Dam. 

As this species and its Pacific slope congener, maculatus, were 
common in the waters of the Canal Zone before the opening of the 
Canal, according to investigations made in 1911 and 1912, crossing 



340 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

over through Culebra Cut, and intermingling of the species would 
be expected. Although maculatus has entered Gatun Lake, as shown 
in the discussion of that species, no evidence indicating that dormitor 
has crossed over to Miraflores Lake and adjacent waters was gained. 

This species is rather close to maculatus, yet the two are readily 
separable by the differences in the scale and anal fin formulae, and 
color. In 20 specimens of dormitor 19 have I, 9 anal rays and one 
has I, 10, whereas in 23 specimens of maculatus, 21 have I, 10 rays 
and one has I, 11, the last partly divided ray having always been 
counted as one. In the same specimens the number of oblique 
series of scales between the upper anterior angle of the gill opening 
and the base of the caudal ranges from 62 to 66, and the complete 
longitudinal rows between the bases of the second dorsal and anal 
from 19 to 22 in dormitor, and 55 to 60 and 17 or 18, respectively, 
in maculatus. In color, dormitor differs principally in having much 
larger and more prominent dark spots on the dorsal, caudal, and 
pectoral fins. Generally the dark lateral band is much more promi- 
nent in dormitor, and it persists more or less in large specimens, 
whereas it is not evident in the larger specimens of maculatus, nor 
even in some of the young. 

This fish reaches a length of about 325 to 375 mm. Although 
used as a food to a limited extent, it is not valued highly. 

This species ranges from Texas to Brazil and the West Indies. 
It is common in brackish and fresh-water lowland swamps and 
streams, and it also ascends rivers in which it occupies shallow 
weedy coves. It has been taken in all suitable localities on the 
Atlantic slope of Panama where collections have been made. Behre 
(1928, p. 311) recorded it from extreme western Panama, from the 
province of Bocas del Toro. 

Gobiomorus maculatus (Giinther). 

Lembus maculatus Giinther, Cat. Fish. Brit. Mus., 1, p. 505, 1859 Andes of 

Ecuador. 
Philypnus maculatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 352, 1916. 

Thirty-one specimens, ranging in length from 40 to 210 mm., 
were preserved, and others were examined in the field. The speci- 
mens were collected in Gatun Lake, Miraflores Lake, Rio Cocoli, 
Pedro Miguel Locks, upper and lower chambers of Miraflores Locks, 
Rio Cabra, and in some small coastal streams crossing the National 
Highway between Campana and La Venta. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 341 

As noted in the preceding paragraph, the species was taken in 
Gatun Lake, the catch consisting of two specimens, 127 and 210 mm. 
long, caught in the lake only a short distance below Madden Dam. 
These two specimens are typical maculatus, that is, they appear to 
be identical with specimens from streams of the Pacific slope of 
Panama not connected with the Canal. Although the two species 
must be living together, as shown by three specimens of dormitor 
and two of maculatus, taken together in one cove of Gatun Lake, 
no indication of cross-breeding is evident. However, a specimen, 
147 mm. long, from Barro Colorado Island has some of the charac- 
ters of both species, but it also differs from both. It agrees with 
dormitor in the scale formula (64-22), and in color; it agrees with 
maculatus in the anal fin formula (I, 10); but it differs from both 
in the more slender body (depth 6.6, and peduncle 11.6 in standard 
length), in the larger eye (5.25 in head, compared with about 6 to 
6.5 in other specimens of about equal length), and in having one 
more spine and one more ray in the dorsal fins, the formula being 
VII-I, 10. In the absence of similar specimens, supplying more 
evidence of cross-breeding, or that a third species is present, the 
specimen is regarded, for the present, as a variant dormitor. 

This fish apparently reaches a length about equal to that of 
dormitor, the largest individual seen being 325 mm. long. 

The range of this species extends from Lower California to 
Ecuador. It lives in environments similar to dormitor and seems 
to be identical with that species in its behavior and selection of food. 

Dormitator Gill. GUAVINA. 

Two very closely related species from the opposite slopes of 
Panama are recognized. The relationship, which is discussed in the 
following accounts, is so close, however, that the species must be 
regarded as doubtfully distinct. 

The common name, guavina, seems to be widely used in Central 
America and the West Indies for the species of this genus and for 
those of related genera. 

Dormitator maculatus (Bloch). 

Sciaena maculatus Bloch., Naturgesch. Ausland., Fische, pi. 299, fig. 2, 

1790 West Indies. 
Dormitaior maculatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 354, 1916. 

Specimens of this species were taken at Fort Sherman (Toro 
Point), and at Cativa, on the Atlantic side. In addition 15 small 



342 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

specimens, ranging in length from 20 to 85 mm., taken in the lower 
flight (east side) of Miraflores Locks, seem to be of this species. 
If the last-mentioned specimens are correctly identified, it would 
appear that a migration from the Atlantic to the Pacific side, through 
the Canal, had taken place. The Pacific drainage representative of 
the genus, namely, latifrons, was not taken in the Miraflores Locks 
when they were dewatered, but was secured there later. The 
relationship between the two species, as shown subsequently, is so 
close that too much reliance must not be placed on the identification 
of juveniles. Other specimens taken in the Pacific drainage certainly 
are separable from the Atlantic ones, and are in entire agreement 
with the differences stated by Meek and Hildebrand (1916, pp. 
353-356), based on a study of specimens collected in 1911 and 1912. 

This species apparently differs from latifrons chiefly in having 
somewhat fewer scales, and rather longer pectoral and ventral fins, 
as shown in the counts and measurements given subsequently. 
Furthermore, the mouth seems to be a little more strongly oblique 
in maculatus than in latifrons, as the cleft anteriorly is generally 
well above the lower margin of the eye, whereas in the latter it 
is usually about at the level of the lower margin of the eye. 

The following measurements and counts are based on seven 
small specimens ranging in length from 45 to 85 mm., no larger 
specimens of this species having been secured during the recent 
investigation: Head 3.2 to 3.4; depth 3.7 to 4; D. VII-I, 8 (if the 
last partly separated ray is counted as 1); A. I, 8 or 9; P. 14; scales 
30 to 33, 7 to 9 complete longitudinal rows between the base of 
dorsal and anal. Snout 3.3 to 4 in head; eye 4 to 4.7; interorbital 
2.5 to 3.2; maxillary 3.3 to 3.5. Pectoral 1.1 to 1.5 in head, 3.7 to 
4.1 in standard length; ventral 1 to 1.2 in head, 3.4 to 3.9 in standard 
length. 

This species, like its Pacific slope relative, lives in still, brackish 
and fresh water, often being found in very shallow warm stagnant 
pools and coves, where it feeds on algae and other plants. Although 
primarily a vegetarian in nature, this species and its relatives have 
been used very successfully in South America for the control of 
mosquito-breeding in water containers. When plants are not present 
they feed on wiggle-tails; they live well in confinement; and are too 
sluggish (or sleepy, as the generic name indicates) to jump out of 
even a brimful container, a difficulty experienced with the top 
minnows, which in nature are far better for mosquito control. It 
must not be assumed that these guavinas are useful in nature for 



FRESH- WATER FISHES OF PANAMA HILDEBRAND 343 

mosquito control, because they feed on wiggle-tails when confined 
in comparatively small containers wherein algae and other plants, 
which constitute their usual food, are absent. Apparently in the 
absence of the usual diet they take what is available and exist on it. 
This fish as now understood ranges on the Atlantic slope from 
North Carolina to Para, Brazil, and the West Indies. During the 
earlier investigations in Panama (1911 and 1912) it was taken in 
many lowland brackish ponds and streams from Porto Bello to 
Toro Point, and Behre (1928, p. 310) recorded it from extreme 
western Panama from the province of Bocas del Toro. 

Dormitator latifrons (Richardson). 

Eleotris latifrons Richardson, Voyage "Sulphur," Fishes, p. 57, pi. 35, figs. 

4, 5, 1837 probably Pacific coast of Central America. 
Dormitator latifrons Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 

10, p. 355, 1916. 

Specimens were taken only in a stagnant pool, wherein they were 
numerous, in a creek near the head of tide on the National Highway 
near Campana, during the recent investigations. Later specimens, 
taken in Miraflores Locks by Mr. Lear, a Locks employee, were 
received. D. latifrons seems to be rather common along the Pacific 
coast of Panama in habitats similar to the first one mentioned 
above, as it was taken in several such places during the earlier 
(1911 and 1912) investigations. Meek and Hildebrand did not see 
it in the Tuyra Basin, but Breder (1927, p. 141) took specimens in 
a stagnant tidal pool near Yavisa in that river basin. 

The relationship between this species and maculatus, as stated 
in the account of the last-mentioned species, is very close. The 
following measurements and counts, based on six specimens ranging 
in length from 47 to 205 mm., are useful in showing the minor 
differences. 

Head 2.75 to 3.1; depth 2.8 to 3.2; D. VII-I, 8 (if the last partly 
divided ray is counted as one); A. I, 9; P. 14 or 15; scales 34 to 36, 
10 to 12 complete longitudinal rows between the base of dorsal and 
anal. Snout 3.1 to 3.8 in head; eye 4.8 to 7; interorbital 2.1 to 2.75; 
maxillary 3.1 to 3.5. Pectoral 1.25 to 1.4 in head, 3.5 to 3.9 in 
standard length; ventral 1.4 to 1.8 in head, 4.3 to 4.7 in standard 
length. 

The bright or even brilliant color of the fish taken March 11, 
1937, from a very stagnant dirty pool, was striking by contrast. 
Bright colors had not previously been noticed by me in other 
specimens, and they may be nuptial, as the brightly colored sped- 



344 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

mens were developing males. Specimens taken later (September 30, 
1937) in Miraflores Locks, by Mr. Lear, upon which Dr. Foster 
based color notes, also were brightly colored. The specimens taken 
by Mr. Lear were schooling in the locks. Dissections made by 
Dr. Foster and by me show that the fish forming the schools were in 
spawning condition. Therefore, the fish apparently schooled to 
carry out their reproduction activities. That this was taking place 
in the locks is interesting. Spawning, then, would appear to take 
place during the rainy season our summer. 

The following notes on color were based on a male 200 mm. long, 
immediately after the fish was caught. Brownish above in advance 
of dorsal, bluish on sides with indications of lighter crossbars; belly 
pale gray; head bluish underneath. Many scales on side have a 
brownish base. Dorsal fin brownish with dark markings and a 
brilliantly red margin; caudal fin similar in color, but without spots; 
anal fin green at base, with dark spots, and the outer two-thirds 
bright red; ventrals bluish green; pectorals wholly pinkish; iris red. 
That there is variation even among adults is evident from notes 
taken by Dr. Foster, based on a fish (sex not stated) taken in Mira- 
flores Locks to which reference was made in the preceding paragraph. 
The following description is condensed after Dr. Foster: 

Body blue-green dorsally to inconspicuously greenish red ven- 
trally. Head slate-colored; iris red. Dorsal fin gray with black 
polka dots and inconspicuous red margins; caudal fin gray; anal fin 
deep maroon, with 2 or 3 rows of blue polka dots near and parallel 
to body, the margin conspicuously white; pectorals and ventrals 
blue-gray. 

This fish ranges from Lower California to Ecuador. 

Eleotris Bloch and Schneider. GUAVINA. 

Three species of this genus occur in Panama. They are highly 
carnivorous, and although a sufficiently large size is attained (at 
least by picta} they are not valued as food, possibly because they 
are covered with a heavy coat of mucus, which gives them a dis- 
agreeably slimy appearance. 

The species are distinguished principally by the differences in 
the size of the scales, their degree of embedding, and by color, as 
pointed out in the following accounts. 

Eleotris picta Kner and Steindachner. 

Eleotris picta Kner and Steindachner, Abhandl. Bayer. Akad. Wiss., Munchen, 
10, p. 18, pi. 3, fig. 1, 1864 Rio Bayano, Panama; Meek and Hildebrand, 
Field Mus. Nat. Hist., Zool. Ser., 10, p. 357, 1916. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 345 

Thirty-one specimens, ranging in length from 22 to 480 mm., 
taken in Pedro Miguel and Miraflores Locks, Miraflores Lake, and 
in streams crossing the National Highway between Campana and 
La Venta, were preserved. Many others were seen and examined. 
The largest individual seen was a male 495 mm. long, which may 
be near the maximum size attained. The indication is that this 
species grows larger than its near relative of the Atlantic slope, 
the largest specimen of that species seen being only 150 mm. long. 
In addition, 21 juveniles, ranging in length from 18 to 20 mm., 
were taken in the lower chamber (west side) of Miraflores Locks, 
in strongly brackish to salt water. None of these juveniles have the 
generically distinctive preopercular spine developed. However, it 
seems evident that the gill openings do not extend forward under 
the eyes, as in Gobiomorus, which has a similar fin ray count, and 
the mouth is large with protruding lower jaw. The young, therefore, 
seem to belong to Eleotris. Although the fins are quite fully devel- 
oped, general pigmentation has not taken place. In general, the 
development is more retarded than in Eleotris pisonis and E. isth- 
mensis of equal size, possibly because picta reaches a larger size. 

The similarity of these young eleotrids and some young marine 
gobies, studied by the writer (1938), is striking. In the eleotrids, 
as in the marine gobies with fully united ventrals, the caudal fin is 
concave, not becoming round until pigmentation is general. The 
color markings of the juveniles, too, are similar, consisting in each 
group principally of black lines composed of short dashes on the 
median dorsal and ventral lines. 

The relationship of this species and pisonis is discussed in the 
account of the last-mentioned species. The distinctive characters 
set forth apply to all the specimens preserved or examined, that 
were not taken in the Canal or waters connected with it, as well 
as to most of the individuals taken in the Canal. One rather notable 
exception, and a few less pronounced ones, which have some of the 
characteristics of both pisonis and picta, however, were found. 

The most notable exception is a male specimen, 345 mm. long, 
taken in Pedro Miguel Locks. It has large scales like pisonis, 
which as in that species are scarcely or not at all embedded in 
advance of the dorsal. This fish has 62 oblique series of scales 
between the upper posterior angle of the gill opening and the base of 
the caudal on one side and 65 on the other, and 19 complete longi- 
tudinal rows between the bases of the second dorsal and the anal. 
In color this specimen agrees with picta, being quite pale ventrally 



346 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

with only scattered brownish dots, and with no indications of dark 
lines along the rows of scales. This specimen, though having the 
characteristic concealed spine on the preopercular margin, differs 
from other specimens in having two small patches of vomerine 
teeth. The presence of these teeth is difficult to explain, as the 
genus is not supposed to possess them. Perhaps this specimen 
is merely a variant in that respect. 

One female, 245 mm. long, from the lower flight of Miraflores 
Locks, though having small scales that are well embedded in advance 
of the dorsal, as characteristic of picta, nevertheless has rather 
definite dark lines along the rows of scales on the sides as in pisonis. 
A few small specimens from Miraflores Lake also have indications 
of dark stripes along the rows of scales, though less distinct and less 
definitely continuous. 

It cannot be stated positively, because of the close relationship 
of the two species under consideration, that the specimens discussed, 
which have some of the characteristics of each species, are hybrids. 
However, the evidence seems to lead to that conclusion. If they are 
hybrids, then it follows that the species have intermingled by passing 
through Culebra Cut, and have cross-bred. As many individuals 
were present in Pedro Miguel Locks when the locks were dewatered 
in 1937 it seems probable that they pass through these single flight 
locks freely. Certainly no reason is evident why the species would 
not intermingle, as no barrier to prevent it seems to be present. 

The sexes in this species may be distinguished by the shape of 
the anal flap, for in the male it is rather narrow distally, with a 
strongly convex to almost pointed margin, whereas in the female it 
is notably broader distally, with an almost straight posterior margin. 
Spawning apparently takes place during the dry season (about 
February to April), as five of seven specimens examined, two males 
and five females, taken February 20 and March 26, 1937, contained 
either large or developing roe. 

Among eight specimens examined for food five had empty 
stomachs. One of the others had ingested an anchovy and the 
second one had fed on small mussels. The species is strictly carniv- 
orous, as shown by these examinations and published accounts. 

This fish is common in Miraflores Lake, and, as already stated, 
many individuals were found in Pedro Miguel Locks when the locks 
were dewatered in February, 1937. The species is not valued as 
food. Large examples offered to colored workmen were refused, 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 347 

possibly because the heavy coating of mucus they always seem to 
possess makes them repulsive. 

This species ranges from Lower California to Ecuador. It has 
been taken in virtually all the streams sampled in the Pacific slope 
of Panama. Though it was not secured in the Tuyra Basin by Meek 
and Hildebrand, it was recorded from there by Breder (1927, p. 142). 

Eleotris pisonis (Gmelin). 

Gobius pisonis Gmelin, Linn. Syst. Nat., p. 1206, 1788 Brazil. 
Eleotris pisonis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 
p. 358, 1916. 

Twenty-four specimens, ranging from 22 to 150 mm. in length, 
were collected in 1935 and 1937 in fresh- water streams at Fort 
Sherman (Toro Point), and Cativa; and in the dry dock at Mount 
Hope, and the lowest chamber (east side) of Gatun Locks. In the 
dry dock and the lowest chambers of Gatun Locks, the water is 
quite brackish to salty. In addition to the specimens listed, three 
juveniles, respectively 14, 15, and 19 mm. long, which apparently 
belong to this species, were taken in the lowest chamber of Gatun 
Locks, together with larger ones already listed. The characteristic 
preopercular spine is well developed in the 19 mm. fish, and it may 
be felt with a fine needle in the 15 mm. one, but it is not yet evident 
in the 14 mm. specimen. The 15 mm. specimen already has a few 
scales on the caudal peduncle where they seem to appear first, but 
the 14 mm. fish remains naked. This smallest specimen also remains 
largely unpigmented, whereas in the larger ones, pigmentation is 
general. 

As this species and its Pacific slope congener, picta, ascend fresh- 
water streams and are fairly common, according to investigations 
made in 1911 and 1912, on both slopes of the Canal Zone in waters 
now included in or connected with the Canal, crossing over from one 
side to the other might be expected. However, no evidence that it 
has taken place was gained from the specimens collected in the dry 
dock at Mount Hope and Gatun Locks, though the situation is 
somewhat different in regard to specimens taken in Pedro Miguel 
and Miraflores Locks, and in Miraflores Lake, as stated in the 
account of E. picta. 

This species differs from its Pacific slope relative, picta, in several 
minor respects, as pointed out by Meek and Hildebrand (1916, 
p. 356). The differences in the size of scales and the degree of 
embedding, together with the differences in color, are the principal 
recognition marks. The present species has somewhat larger scales 



348 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

(59 to 68, most frequently about 64 in a lateral series, and about 18 
complete longitudinal rows between the bases of second dorsal and 
anal, whereas picta has respectively 63 to 75, most frequently 67 to 
69, and about 22), and they are not as greatly reduced in size in 
advance of the dorsal. Furthermore, they are scarcely or not at all 
embedded on the head in the present species, but rather fully in 
picta. In general, pisonis is darker ventrally, the color of preserved 
specimens being uniform brown, and the rows of scales along the 
sides are more or less distinctly marked with black lines. The ventral 
surface of the head, chest, and belly in picta, on the other hand, is 
rather pale, and is dotted, spotted, or marbled with brown, there 
being much variation among specimens, and there are no continuous 
dark lines along the rows of scales. Small specimens frequently have 
a dark band extending backward from the snout and eye. This 
band is much more frequently present in the Pacific slope specimens 
than in the Atlantic ones. 

This species ranges from Florida to Brazil. 

Eleotris isthmensis Meek and Hildebrand. 

Eleotris isthmensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 359, 1916 Mindi, Canal Zone. 

Eleven specimens, ranging from 20 to 60 mm. in length, were 
collected in 1935 and 1937 at Fort Sherman (Toro Point) and at 
Puerto Pilon in fresh water, and in brackish to salt water in the 
lowest chamber of Gatun Locks. In addition, 22 juveniles, ranging 
from 14 to 18 mm. in length, which evidently belong to this species, 
were taken in the lowest chamber of Gatun Locks (east side). The 
smallest of these specimens already are well clothed with ctenoid 
scales posteriorly. The preopercular spine, characteristic of the 
genus, is present, and pigmentation is general. The caudal fin, 
however, remains concave to square. Development seems to be a 
little farther advanced in these fish than in young of the same size 
of pisonis, and much ahead of young of similar size of picta. 

This species apparently agrees with pisonis in all respects, except 
that it has larger scales 045 to 53 oblique series between the upper 
posterior angle of gill opening and base of caudal, and 12 to 14 
complete longitudinal rows between the bases of the second dorsal 
and the anal), which seem to be less adherent. The species appar- 
ently reaches even a smaller size than pisonis. The largest specimen 
known is only 85 mm. long, and those 50 to 60 mm. long are sexually 
fully mature. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 349 

The species is known only from the Atlantic slope of Panama, 
where it has been taken in or near brackish water. It apparently 
is rather less common than pisonis. 

Guavina guavina (Cuvier and Valenciennes). 

Eleotris guavina Cuvier and Valenciennes, Hist. Nat. Poiss., 12, p. 223, 1837 

Martinique. 
Guavina guavina Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 

p. 360, 1916. 

No specimens of this species, which seems to be rather rare in 
Panama, were secured in 1935 nor 1937. Our earlier collections (1911 
and 1912) contained only five specimens, collected in brackish 
ditches and creeks at Fort Sherman (Toro Point) and Colon. 

The range of this fish extends on the Atlantic coast from some- 
where in Mexico, through the West Indies, to Brazil. 

Leptophilypnus Meek and Hildebrand. 

Microeleotris Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 
p. 362, 1916 type M. panamensis. 

The generic name, Microeleotris, is placed in synonomy here for 
reasons stated in the account of Leptophilypnus fluviatilis. 

Leptophilypnus fluviatilis Meek and Hildebrand. 

Leptophilypnm fluviatilis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

. Ser., 10, p. 361, 1916 Mindi, Canal Zone. 

Microeleotris mindii Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 
10, p. 364, 1916 Mindi, Canal Zone. 

This species was numerous in the "manholes" in the floors of 
the locks, especially in the chambers in which the water was nearly 
fresh. The fish could be seen clinging, very goby-like, to the walls 
of the holes in which water remains after the floors of the locks 
have been drained or pumped dry. The fish are not easily caught, 
however, as they cling close to the concrete walls of the "manholes," 
and are able to avoid nets fairly successfully. Specimens were 
secured in Gatun Locks: (a) uppermost chamber 27 specimens, 
15 to 43 mm. long; (6) middle chamber two specimens, 38 and 40 
mm. long; and (c) lowermost chamber one specimen, 35 mm. long; 
in Pedro Miguel Locks, 35 specimens, 20 to 33 mm. long; and in 
the upper chamber of Miraflores Locks, 16 specimens, 28 to 48 mm. 
in length. There are none from the lower chamber. In addition, 
three specimens were seined in Gatun Lake at Barro Colorado 
Island, and one in Miraflores Lake. 



350 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

It was recorded only from a brackish creek at Mindi, Canal 
Zone (Atlantic side) by Meek and Hildebrand (1916, pp. 361-364), 
who recorded similar specimens from the same vicinity under the 
name Microeleotris mindii; and also M. panamensis from the Pacific 
slope from the Rio Chorrera and the Rio Juan Diaz. It should be 
noted that M. panamensis was not taken on the Pacific slope of the 
Canal Zone. The specimens now at hand cannot be separated defi- 
nitely as to the genera Leptophilypnus and Microeleotris, which were 
described as differing chiefly in the width of the dentary bones, 
or rather as to whether they met at or near the posterior angles 
of the mouth. In Leptophilypnus they were described as meeting, 
leaving an oval-shaped naked area at the chin, whereas in Micro- 
eleotris these bones were said to be narrow and not meeting. I have 
re-examined paratypes of all three species placed in these genera, 




"V 



FIG. 10. Leptophilypnus fluviatilis Meek and Hildebrand. Specimen 50 mm. 
long. (From drawing by Andrew Pizzini.) 

in connection with the specimens recently collected. The paratypes 
of L. fluviatilis are quite uniform as to the width and the approach 
to each other of the dentary bones, but the type material of M. 
mindii shows considerable variation in this respect, and in the 
material recently collected there is a wider degree of variation. 
In some specimens the bones meet and in others they are variously 
separated, some being fully half an eye's diameter apart. Appar- 
ently, the way the fish happens to die, that is, with the mouth 
open and the gill covers spread, makes a difference, but that does 
not account for the whole variation. It seems to be true also that 
typical examples of M. mindii have a wider head and a deeper 
caudal peduncle. However, the intergradation is complete. No 
tangible differences in the number of fin rays or scales were found 
among the type material, and I find none among the specimens at 
hand. I have concluded, therefore, that the genus Microeleotris is 



1938 



FRESH- WATER FISHES OF PANAMA HILDEBRAND 



351 



not valid and that M. mindii is a synonym of L. fluviatilis. How- 
ever, M. panamensis is a valid species, differing from fluviatilis 
in having smaller scales, in having (usually at least) 8 instead of 9 
soft rays in the second dorsal and in the anal, and in having a 
broader head, as stated by Meek and Hildebrand (1916, p. 363), but 
generically it is not distinct. 

As L. fluviatilis was not taken on the Pacific slope of the Canal 
Zone before the opening of the Canal, it seems probable that it has 
crossed over from the Atlantic. This fish, as already stated, was 
numerous in those chambers of the locks at both ends of the Canal 
that are fairly fresh, where it seemed to be peculiarly at home. No 
reason is known why the members of the species should not migrate 
freely between the locks at the opposite ends of the Canal. This 
fish is known only from the Canal Zone. 






FIG. 11. Leptophilypnus fluviatilis Meek and Hildebrand. Ventral surface 
of heads of three specimens, showing variation in width and in space between 
dentary bones. 

Leptophilypnus panamensis (Meek and Hildebrand). 

Microeleotris panamensis Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 
Ser., 10, p. 363, 1916 Rio Juan Diaz. 

In our earlier work this species was placed in the genus Micro- 
eleotris, which proves to be invalid. However, panamensis has been 
shown to be a valid species. It is not in the present collection, and 
remains known only from the type material from the Rio Chorrera 
and the Rio Juan Diaz, which was re-examined in part. 

Euleptoeleotris gen. nov. 

Genotype Euleptoeleotris clarki sp. nov. 

This genus agrees with Eleotris, (a) in having broad bands of 
teeth on the jaws and none on the vomer, (6) in having the gill 
openings restricted (extending scarcely to margin of preopercle), 
and (c) in having a somewhat concealed downward projecting 



352 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

spine on the lower posterior angle of the preopercular margin. 
It differs from that genus, however, (a) in having a much more 
slender body (depth about 6.5 to 8 in standard length), (6) in having 
much smaller scales (125 or more in a lateral series), which are all 
cycloid, and (c) in having more numerous simple or rudimentary 
caudal rays (11 to 13 above and below), which extend much farther 
forward on caudal peduncle, about to joint between the third and 
fourth vertebrae. Vertebrae about 9 or 10+15 or 16. 

Euleptoeleotris clarki sp. nov. 

Type from Miraflores Locks, Canal Zone. No. 106508 United 
States National Museum. Female. Total length 127 mm., standard 
length 104 mm. 

Description of the type. Read 4.5; depth 8; D. VI-1, 13; A. 1, 11; 
P. 18; scales too small to enumerate accurately, about 175 in a 
lateral series. 

Body very slender, compressed posteriorly; depth of caudal 
peduncle 2.4 in head; head depressed, the width exceeding the depth 
by fully an eye's diameter; snout rather long, 5.1 in head; eye small, 
directed upward only slightly, 10.2; interorbital 8.2; mouth large, 
oblique, lower jaw strongly projecting; maxillary reaching under 
middle of eye, 3.1 in head; gill openings restricted, extending for- 
ward scarcely to preopercular margin; scales reduced in size anteri- 
orly, but scarcely embedded; head with many rows of pores, 
especially around the eyes; dorsal fins well separated, none of the 
spines of the first reaching the origin of the second if deflexed, 
the origin of the second about equidistant from the posterior margin 
of the eye and the base of the caudal; caudal somewhat pointed, 
the longest rays nearly as long as the head, with 12 rudimentary 
rays above and 11 below, extending forward on caudal peduncle a 
distance fully equal to the depth of the peduncle; anal fin similar to 
second dorsal, its origin about an eye's diameter posterior to origin 
of second dorsal; ventrals rather small, 2.1 in head; pectorals notably 
larger, pointed, the middle rays being somewhat produced, reaching 
about half their length beyond tips of ventrals, 1.5 in head. 

Color of preserved specimen uniform light brown above, paler 
ventrally, the chest and abdomen being pale with many dark dots; 
a dark blotch behind upper part of gill opening; sides with indi- 
cations of pale cross lines except on peduncle. Dorsal and pectoral 
fins rather pale with blackish spots, the latter with a dark blotch 
at base; caudal darker, with indications of black spots; anal and 
ventrals pale, with scattered dark points. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 353 

Variations noticed in the paratypes are as follows: Head 4 to 4.6; 
depth 7.5 to 8.5; D. VI-I, 12 or 13; A. I, 10 or 11; P. 17 to 19; rudi- 
mentary rays of caudal 11 or 12 both above and below peduncle; 
scales too small to enumerate accurately, about 150 to 175; vertebrae 
9+15 or 16. Snout 5 to 5.6 in head; eye 8.4 to 10.2; interorbital 
5.5 to 8.5; maxillary 2.8 to 3.2; ventral fin 2 to 2.4; pectoral 1.4 to 
1.8; caudal peduncle 2.4 to 3. Some specimens are paler than 
others. The paler specimens have no definite dark blotch on the 
base of the pectoral. 

The sexes in this species, as in Eleotris, can be recognized by the 
shape of the anal flap, that of the female being broadly rounded 
to nearly square distally, whereas in the male it is somewhat pointed. 
In general, the dorsal and anal fin rays seem to be somewhat higher 
in males than in females. It is not evident that the caudal fin is 
longer in males than in females, nor that it increases in proportionate 




FIG. 12. Euleptoeleotris clarki gen. et sp. nov. Type, female, 127 mm. long. 
(From drawing by Andrew Pizzini.) 

length with age, the length varying from slightly shorter to slightly 
longer than the head. 

This species is represented in the collection by 11 specimens, 
ranging in length from 63 to 150 mm., all taken in Miraflores Locks, 
partly in the upper and partly in the lower chambers. 

It affords me pleasure to name this species for Dr. Herbert C. 
Clark, director of the Gorgas Memorial Laboratory, who made it 
possible to carry on the investigations resulting in the discovery of 
this and several other new species of Panamanian fishes. 

Euleptoeleotris Shropshire! sp. nov. 

Type from a dry dock, Mount Hope, Canal Zone. No. 106507 
United States National Museum. Female. Total length 53 mm., 
standard length 42 mm. 

Description of the type. Head 4.1; depth 8.2; D. VI-I, 10; 
A. I, 9; P. 18; scales too small to enumerate accurately, probably 
about 125 in a lateral series. 



354 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 

Body very slender, compressed posteriorly; depth of caudal 
peduncle 3.4 in head; head depressed, fully an eye's diameter wider 
than deep; snout moderately long 5.1 in head; eye moderate, scarcely 
directed upward, 5.8; interorbital 9.3; mouth large, oblique, lower 
jaw projecting; maxillary reaching middle of eye, 3.3 in head; gill 
openings restricted, not quite extending forward to margin of pre- 
opercle; scales somewhat reduced in size anteriorly, scarcely em- 
bedded, all cycloid; head with many rows of pores about the eyes; 
dorsal fins far apart, none of the spines of the first reaching the 
second if deflexed; origin of the second dorsal almost equidistant 
from posterior margin of the eye and base of caudal; caudal fin 
somewhat pointed, the longest rays equal to length of head, with 11 
rudimentary rays above and 11 below, extending forward on the 
caudal peduncle a distance about equal to depth of peduncle; anal 
similar to second dorsal, its origin scarcely an eye's diameter pos- 
terior to origin of second dorsal; ventrals small, 2 in head; pectorals 
much larger, pointed, reaching nearly half their length beyond tips 
of ventrals, 1.5 in head. 

Color of preserved specimen light brown, pale underneath; a 
rather conspicuous black blotch behind upper part of gill opening; 
sides anteriorly with suggestions of pale cross-lines. Dorsal and 
caudal fins somewhat darker brown than the back, without definite 
dark spots; anal fin paler brown than dorsals and caudal, also 
unspotted; ventrals and pectorals pale, with brownish points. 

A single paratype, a male, 55 mm. long, taken in the mouth 
of a brackish creek at Puerto Pilon (Atlantic side) is at hand. The 
following proportions and counts are based on this specimen: Head 
3.5; depth 6.5; D. VI-1, 10; A. I, 9; P. 17; scales too small and irregular 
to enumerate, probably about 125 in lateral series. Snout 5.3 in 
head; eye 6; interorbital 9.3; maxillary 3; caudal peduncle 3.2. 
The paratype, being a male, has higher dorsal and anal fins than the 
holotype, and the caudal fin is longer and more sharply pointed, 
the longest rays a little longer than the head. This specimen, 
including the fins, is much darker brown than the holotype, and the 
vertical fins (especially the caudal) have definite black spots. No 
dark blotch is evident, however, behind the upper part of the gill 
opening as in the holotype. 

The two small specimens of this species are insufficient to deter- 
mine the exact difference between it and clarki. Apparently the 
second dorsal and anal fins are a little shorter in shropshirei, each 
having 1 to 3 fewer rays, as shown in tjie descriptions. Furthermore, 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 355 

the scales, though they cannot be enumerated definitely, apparently 
are larger in shropshirei. It is judged from the fully developed fins 
(those of the male being somewhat produced) and anal flap that 
the small specimens of shropshirei are sexually fully mature. A 
specimen of clarki of somewhat similar size (63 mm. long) at hand 
has this secondary sexual character little developed and so im- 
perfectly that it is impossible to determine the sex by its shape. 
This difference in development suggests that the Atlantic coast 
species, as in Eleotris, reaches maturity at a smaller size, and also 
that it probably attains a smaller size. E. shropshirei apparently 
has a larger eye and longer pectoral and ventral fins, as shown in 
figures 12 and 13. 

As it is not evident from the material at hand that the species 
of this genus enter strictly fresh water, it apparently may be assumed 




FIG. 13. Euleptoeleotrisshropshireisp. nov. Type, female, 53 mm. long. (From 
drawing by Andrew Pizzini.) 

that no crossing over from one side to the other through the Canal 
has taken place. 

This species is named in honor of J. B. Shropshire, supervisor 
of malaria control for the United States Army in Panama, who took 
the holotype in the dry dock at Mount Hope, when it was pumped 
out, and who assisted the writer in many other ways while he was 
working in Panama in 1937. 

Hemieleotris latifasciatus (Meek and Hildebrand). 

Eleotris latifasciatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 68, 1912 Rio Cardenas, Pacific slope, Panama. 
Hemieleotris latifasciatus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 365, pi. 32, 1916. 

A single specimen, 65 mm. long, was taken in the Rio Pacord 
(Pacific slope). 

This species is reported from the Pacific slope from Costa Rica 
and Panama to southern Colombia. 



356 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. XXII 
Awaous Cuvier and Valenciennes. 

Awaous Cuvier and Valenciennes, Hist. Nat. Poiss., 12, p. 97 (quarto ed., 
p. 73), 1837; Steindachner, Sitzber. Akad. Wiss., Wien, 42, p. 289 (I860?); 
Ginsburg, Proc. U. S. Nat. Mus., 82, art. 20, pp. 20-21, 1933. 

As shown by Ginsburg, the name Awaous dates from Cuvier 
and Valenciennes, 1837, rather than from Steindachner, 1860 or 
1861, and has clear priority over Chonophorus Poey, 1860. 

Awaous taiasica (Lichtenstein). 

Gobius taiasica Lichtenstein, Abhandl. Preuss. Akad. Wiss., Berlin, 1822, 

p. 273 Brazil. 
Awaous taiasica Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 

p. 366, 1916. 

This fresh-water goby is represented in the recent collections 
by four specimens, 57 to 85 mm. long, all taken by J. B. Shropshire 
in a fresh-water stream at Fort Sherman (Toro Point), where Meek 
and Hildebrand did not obtain it in 1911 and 1912, although they 
collected there. The specimens conform well to the description of 
specimens from the Chagres Basin by Meek and Hildebrand (1916, 
p. 367). Behre '(1928, p. 311) recorded it from creeks flowing into 
Almirante Bay, western Panama. The probable range of this 
species was given by us (1916, p. 368) as extending on the Atlantic 
slope from Mexico to Brazil. Eigenmann (1922, p. 216) since has 
shown that another species inhabits the Atlantic slope of Colombia 
(Atrato and Magdalena basins), which he named A. decemlineatus. 
He did not state whether taiasica also occurs there. If not, the 
Panama fish probably also is different from the Brazilian form on 
which taiasica is based. If that be true, which cannot now be 
determined for want of time and material, the Panama species, 
unless one of the several supposed synonyms of taiascia based on 
Central American, Mexican, and West Indian specimens is available, 
would be without a name. 

Awaous transandeanus (Giinther). 

Gobius transandeanus Giinther, Cat. Fish. Brit. Mus., 3, p. 62, 1861 western 

Ecuador. 
Awaous transandeanus Meek and Hildebrand, Field Mus. Nat. Hist., Zool. 

Ser., 10, p. 368, 1916. 

This species is represented by five specimens, ranging in length 
from 17 to 51 mm., all taken in small coastal streams between 
Campana and La Venta. Juveniles were common on sandy bottom 
in very shallow quiet water in a small stream near La Venta, but 
they were so small and slender that they mostly escaped through 
the meshes of a bobbinet seine. 



1938 FRESH- WATER FISHES OF PANAMA HILDEBRAND 357 

The differences between this and the Atlantic slope form seem 
to be correctly set forth by Meek and Hildebrand (1916, p. 366). 
Dark crossbars present in this species, but not in taiasica, are espe- 
cially prominent in juveniles. 

Eigenmann (1922, p. 216) gave the range of this species as 
extending southward on the Pacific slope to Colombia and Ecuador. 
Northward it ranges to Mexico. 

Sicydium salvini Grant. 

Sicydium salvini Grant, Proc. Zool. Soc. Lond., 1884, p. 159, pi. 12, fig. 2 
Panama; Meek and Hildebrand, Field Mus. Nat. Hist., Zool. Ser., 10, 
p. 369, 1916. 

This species is not in the present collection. It is known from 
both slopes of central Panama, and ranges to the Magdalena Basin 
in Colombia and to western Ecuador. 

Sicydium pittieri Regan. 

Sicydium pittieri Regan, Ann. Mag. Nat. Hist., (7), 19, p. 260, 1907 Rio 
Grande de Terraba, Costa Rica. 

This species is included in the Panama fauna on the basis of a 
record by Behre (1928, p. 312), who secured six specimens in a 
small stream tributary to the Rio Chiriqui del Tire (Pacific slope), 
western Panama. 

This fish apparently differs chiefly from Sicydium salvini, the only 
other species recorded from Panama, in the naked area on the median 
part of the belly. However, Eigenmann (1922, p. 214) found a 
naked area, also, in small specimens of salvini. The fin-ray and 
scale counts of the two species seem to agree. 

The range, as far as known, is Costa Rica and western Panama; 
possibly on the Pacific slope only. 

REFERENCES 
BEHRE, ELLINOR H. 

1928. A List of the Fresh Water Fishes of Western Panama between Long. 
81 45' and 83 15' W. Ann. Carnegie Mus., 18, pp. 305-328, 2 pis. 

BREDER, C. M., JR. 

1925. Notes on Fishes from Three Panama Localities, Gatun Spillway, Rio 

Tapia, and Caledonia Bay. Zoologica, 4, No. 4, pp. 137-158, figs. 33-38. 
1925. New Loricariate, Characin and Poeciliid Fishes from the Rio Chucu- 

naque, Panama. Amer. Mus. Nat. Hist. Nov., No. 180, 9 pp., 7 figs. 
1927. The Fishes of the Rio Chucunaque Drainage, Eastern Panama. Bull. 

Amer. Mus. Nat. Hist., 57, pp. 91-176, 10 figs., 5 pis. 
1933, The Fishes of Barro Colorado, Gatun Lake, Panama. Zoologica, 9, 

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